BCM Community
Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Jim Blackwood on October 12, 2019, 07:11:46 AM
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This job will be coming up soon, possibly should be done as one of the first things to make it easier to make things plumb and get lines to drain and such. I've seen some pretty slick systems on here and will probably want to find those threads and link to them for the resources that are there. So anyway what I see as being desirable features if we were to take a clean sheet look at it would be the following:
*Does not interfere in any way with normal suspension operation, including Kneel and rear lift/lower functions. Does not introduce any undesirable characteristics or modify the normal handling of the bus.
*Full manual/override operation mode with the least possible power requirements. This means the battery switch can be cut off and shore line disconnected and the coach won't settle. Impossible to achieve? Some would say so, probably a function of time and minute leaks. Next best, an external air line or extension cord compressor to maintain the air supply. Possible, but practical? IDK,YTM. Sure would be handy. Capable of fully inflating or deflating bags individually for maintenance and maximum flexibility.
*Full auto mode where you set the brake, hit a switch and walk away. Coach levels itself and stays there. The holy grail of RV living. What's it take to do it?
*Most importantly, maintainable by the average bus nut. This means no complex microprocessor controls.
So I'm thinking the heart of the auto-leveling system could be a set of mercury level switches. Simple uncomplicated mechanical devices that have very few failure modes. From there to control relays, and from there to air solenoids. Not a real complex system I think and easy to troubleshoot. Might even be possible to eliminate the relays.
The manual control system would mainly be double throw switches, levels, and perhaps some gages. That leaves the interconnection between the solenoids and the air system, and that's where I'm short on information, not having made it down to Louisville yet to get the maintenance manual. I don't know how simple or complex those tie-ins would have to be. So what do you guys think? Something you feel like kicking around a little bit?
Jim
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I can comment on only one part of this. Yes, it is possible to have a bus hold it's position for an extended period of time. Our 45-year-old GM will hold for months on end, and it did so throughout last winter while parked.
All that said, getting an old bus to stay at height requires a tedious and difficult process of tracking down every air leak, including all the internal ones that can't be found with a spray bottle and soapy water.
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Project justification?
Just for the principle of it... I am a big fan of doing unique things, designing interesting stuff, executing same, never mind what the herd says, however...
Where are you camping that this will be required?
How often?
A lot of complex work, both initially and ongoing, to maintain air integrity for how little use?
That said, keeping all the over-the-road functionality separate and functioning is a good idea.
Adding the "E" model capability to run the whole coach at "high ride" as well as the "D's" "rear raise" has its uses, consider that ability in your design.
Happy coaching!
Buswarrior
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My current bus came with a nice leveling system from the previous owner. Switches at the dash controlling electric solenoids to raise and lower each corner. Nice to have: just throw my phone on the floor and use the level app to level the coach in about a minute.
My old Courier 96 (and every RV I ever owned before) just had a half dozen 2X6 boards I carried in the baggage tank I used to drive over to level for the night. Close enough, and easy enough. Didn't take more than 10 minutes. By the way, 80% of overnight spots are level enough anyway, unless you are really fussy.
JC
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Seems like sticking with basics would be the key here. Maybe bells and whistles wouldn't be too hard to add later but I think it makes more sense to stick with what the bus has to begin with. In my case that does include kneel and rear raise but I think that's a side benefit at present.
I don't think it has to be complex. Let's consider a simplest case, making some assumptions that may or may not be valid. First assumption: each air bag has a solenoid control valve that can pressurize and vent the bag. I know the air ride system is more complex than that but for now this works as a dividing line between old and new so everything I will suggest lies on the new side of this line. It will undoubtedly have to change as the exact characteristics of the old become apparent.
So, here's where it gets really simple. Probably stupidly so but at least it is a starting point: For the autolevel, simple basic mercury switches. You can still buy those and they will handle solenoid level current with robust reliability. Various configurations are available, it should be possible to buy them in a 3 pole leveling switch which makes the rest of this dead easy. If not, two double pole units can be combined to make a leveling switch. We need at least two of those. Connect one to control the air solenoids across the main axle and you have side-to-side leveling. As a practical matter it may take two, wired opposite each other, one for each side. Then another switch connected to both front air solenoids for long axis leveling and a power switch to turn it on. I think that about does it. For the manual side double throw rocker switches to override the mercury switches should be about all that is needed. That's pretty simple and basic.
As for justification, uh, to like, level the coach? Lots of places I'd expect to park will not be level, in fact I'd go so far as to say 90% will NOT be level, probably more than that. I built a tripod hydraulic system on my last RV and you can trust me when I say I feel deprived without it. That system had very long legs, far more than anything you are likely to see on an RV today but by damn I used them. I don't expect anything like that but it sure would be nice if the rig could sit level outside my shop without planks under the wheels.
Jim
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Jim, you and I have the same model bus so I am very interested in how this can be done. Any more progress since this last post?
Jared
Seems like sticking with basics would be the key here. Maybe bells and whistles wouldn't be too hard to add later but I think it makes more sense to stick with what the bus has to begin with. In my case that does include kneel and rear raise but I think that's a side benefit at present.
I don't think it has to be complex. Let's consider a simplest case, making some assumptions that may or may not be valid. First assumption: each air bag has a solenoid control valve that can pressurize and vent the bag. I know the air ride system is more complex than that but for now this works as a dividing line between old and new so everything I will suggest lies on the new side of this line. It will undoubtedly have to change as the exact characteristics of the old become apparent.
So, here's where it gets really simple. Probably stupidly so but at least it is a starting point: For the autolevel, simple basic mercury switches. You can still buy those and they will handle solenoid level current with robust reliability. Various configurations are available, it should be possible to buy them in a 3 pole leveling switch which makes the rest of this dead easy. If not, two double pole units can be combined to make a leveling switch. We need at least two of those. Connect one to control the air solenoids across the main axle and you have side-to-side leveling. As a practical matter it may take two, wired opposite each other, one for each side. Then another switch connected to both front air solenoids for long axis leveling and a power switch to turn it on. I think that about does it. For the manual side double throw rocker switches to override the mercury switches should be about all that is needed. That's pretty simple and basic.
As for justification, uh, to like, level the coach? Lots of places I'd expect to park will not be level, in fact I'd go so far as to say 90% will NOT be level, probably more than that. I built a tripod hydraulic system on my last RV and you can trust me when I say I feel deprived without it. That system had very long legs, far more than anything you are likely to see on an RV today but by damn I used them. I don't expect anything like that but it sure would be nice if the rig could sit level outside my shop without planks under the wheels.
Jim
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Go to the HWH site and look at the 'Air Level System" not the Active Air System just the plain old air leveling system and you can get good ideas using just a few solenoid valves it been used for years
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I have a three way (2 rear 1 front) leveling system that utilizes the normal automatic leveling valves going down the road, then I can manually turn them off and add or exhaust air to level my bus. It's great-takes all of one minute to level. Good Luck, TomC
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Go to the HWH site and look at the 'Air Level System" not the Active Air System just the plain old air leveling system and you can get good ideas using just a few solenoid valves it been used for years
HWH site?
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HWHcorp.com
But if it is so common why isn't it widely used, and why don't we have a write up in Bus Conversions Magazine telling us how we can implement it, from the most basic manual system all the way to full on electronically controlled? Or maybe I missed that?
The HWI site seems to have some info but it is hard to find. If you get into the tech section, at least there is a search window, if you can figure out the right search terms. Who'll be the first to post a link to a page that is actually helpful?
Jim
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I'll start:
http://server51.hwhcorp.com/?page_id=64295#_3-1__What
Jim
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I'll start:
http://server51.hwhcorp.com/?page_id=64295#_3-1__What
Jim
It been used for years on RV nothing fancy MCI,Prevost and even Eagle used the system all manual control valves no electronics I have pieces from one in my shop like the tiny 2 cylinder air compressor 12v from a Foretrave from the 80's
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I'd sure like to see an article in the magazine on it, with schematics, component pictures and such.
Jim
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Written by bus nuts, for but nuts.
Bcm
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you don't get any simpler then this . 1 air line to each corner
( no connections from start to finish ) and 1 air line ( feed ) to the controller . push to add air pull to remove air
no solenoids or power at all just air
https://photos.app.goo.gl/wbVyn2RkJqSFjuEy9
dave
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Dave, how are you hooked into your air bags?
Jim
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removed the original lines from the leveling valves and installed the new lines . before you do anything you need to measure the height from a level surface from the road to in my case the lower belt line at all corners ( wheels ) . record it and that is the ride height you want when driving . after the system is installed then you set the road height from the control unit at each corner by pushing in on each valve until you get the same height . record that and that is the level you want when driving . the rest is the adjustment when you are parked as all you do is adjust the air up or down for the proper level . very simple .
in the 10 years I had the M C I there was never any problems with the system , it would hold the level for months .
dave
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Sounds simple, but when you say record the height, how are you doing that? I picture walking around the coach with a yardstick, adjusting the air, rinse, repeat however many times it takes?
Jim
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Sounds simple, but when you say record the height, how are you doing that? I picture walking around the coach with a yardstick, adjusting the air, rinse, repeat however many times it takes?
Jim
On initial set-up, yes, then you take note of the air pressure applied to each corner, and you have your running heights/pressures, barring significant addition or removal of weight from the coach, in which case, out you go with your yardstick to set new targets.
Hard to beat the simplicity of 4 push/pull manual valves with accompanying individual gauges.
Happy coaching!
Buswarrior
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Sounds good to me. I just ordered four valves:
Order summary
Manual Paddle Valve Switch Control Air Ride Suspension AirLift Performance 21703
Manual Paddle Valve Switch Control Air Ride Suspension AirLift Performan...
Total: $53.72
https://www.ebay.com/itm/112611240096
...and some levels. Since I happen to have a matched set of four 0-150 psi air gages I'll use that plus a similar one if I need it. Is that for your auxiliary air compressor?
I can install a gage panel down to the right against the defroster/AC cover.
Those valves look pretty good and got nothing but good reviews and the price was very good. I may put those in the left hand switch panel if there's room. Might depend on where I put the levels. I'd liek to be looking in about the same area while leveling. Anyway that's an important next step because if I can level the coach that way it'll make interior construction easier. Probably install the system and do the levels last. I'm guessing you just used standard 1/4" air brake line and fittings?
Jim
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yes that is correct
" On initial set-up, yes, then you take note of the air pressure applied to each corner, and you have your running heights/pressures "
after I recorded the pressure's it never changed much as I never over loaded any corner . some times I would add a little more air to the rear if I was pulling a trailer.
I made sure there were no connections in each line to the air bags so no leeks . I had to make a box to install the valves and gauges in that was deep as there are a lot of t 's for the connections and it takes up a far amount of space box was about 9 " x 6 " buy 4 " deep and I installed it right beside my driver seat . I used the 5 th gauge for incoming air and yes 1/4 " air lines dot and all fittings were brass not push in crap
https://photos.app.goo.gl/nUQrHKo3pcPgyiF96
dave
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https://www.mcicoach.com/service-support/serinfo/serinfo12D.htm
The above link should take you to an explanation of the kneeling feature on MCI 102D series busses. There is a second bulletin for the electrical side. I got there with a search and I'm not sure I can get back there, but the info is available if we can find it.
So reading through the explanation, as regards the front axle it seems this Kneel feature might give us a handy way to level that end of the bus, with possibly as much as 12" of adjustment, more likely a bit less. The ride height spec is 11".
The key is Sol1 (NO) and Sol2. Now Sol2 is normally open, supplying air from the leveling valve. During kneeling air is vented through Sol1 which is de-energized. It can be energized to raise the bus. What we need to sort out is a way to raise or lower the air pressure on demand with minimal or no changes to the existing plumbing, the electrical side being generally easier to modify. However, having the air control panel in the front LH bagage bay seems to open some options.
I've not sorted it out yet. We can possibly either do it through Sol2 via the LH leveling valve, although that would seem at first to require extra plumbing, or possibly through SOL1 directly although that would seem to require the solenoid to stay energized. From there it gets more complicated since we want to add a little air and then seal it off. Or alternatively, provide either a regulated pressure or a switched supply depending on coach level condition. Probably best to keep those two options in mind for later.
If I can find similar pages for the operation of the leveling system (and also the rear suspension) it should be possible to sort something out that will suit our needs. Just something I happened across.
Here's the electrical side:
https://www.mcicoach.com/service-support/serinfo/serinfo12E.htm
Reading through this it seems an electrical solution could be feasible.
Jim
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Ideally I think that maybe this can be done without having to get under the bus. That would be a plus.
Jim
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Is the front not a single circuit of air? It will go up and down, but no side to side control?
If your DL has the option to raise its skirts at the rear, getting that halved so each side back there is controlable would be neat, and then you have your 3 legged stool.
As for powered or not, the coach was wired from a seated coach mindset, swap NO for NC, and vice versa, because you need it to work from a camper mindset.
Happy coaching!
Buswarrior
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And designed so that a single dash switch will put everything to "high ride"
Way too many places to drag a 45 foot coach on the ground, getting in and out of parking lots, etc.
Like an excited cat, up on tip toes, back arched, fur on end, maximum clearance underneath...
Happy coaching!
Buswarrior
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Good idea.
Well, I've not located the leveling valves on the front yet, apparently the left one controls rode height and the right one controls a switch so that's a bit of a puzzle, but the line from the right front bellows goes into the spare tire well and to what looks like a manifold block. Not sure about the left one yet but they are both supposed to go to some complex double check valve/maybe shuttle valve thingey somewhere, maybe that mess with all the green 3/8" hoses connected to it. Or that may be something else entirely, looks like they didn't use that valve for another year or so.
Anyway it looks like one of those hoses off the manifold block goes to a small air tank in the left front compartment under the driver. Looks like an accumulator because I think there's only the one line. Maybe it improves ride quality.
Unfortunately each drawing leaves out critical information and my bus doesn't exactly match any of the drawings, so there we go. Here's a shot of my control panel.
By inference it would seem the two sides are T'd together but I have no actual proof of that yet. Be nice if I could just find a spot to add air, power off, and raise the front. But so far it may not be possible without at least another valve. Even then I don't know what the manifold block in the spare well does to it. It's quite the puzzle.
Jim
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Similar to my D3.
It is frustrating, the documentation for the MC8 was exact and detailed.
Someone at MCI must have put an intern in charge of the books during these years, and intern who was focused on nothing to do with accuracy or completeness...
Happy coaching!
Buswarrior
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OK, now that valve at the bottom with the white 1/4" line coming out of it. Do you have any idea where that line goes or what that valve does? Any chance it goes to the kneel switch outside the door? It looks like we have exactly the same controls, so maybe we can figure this out.
My trip down to the Louisville MCI is growing closer and I plan to ask about the maintenance manual when I get there and hope someone can come up with the right one. I hope they have something better than the one I downloaded. In the meantime it looks like tracking down lines is going to be the way of it.
Jim
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More info from direct observation. First, the switches by the door are electric, not pneumatic. Second, the manifold block in the spare tire well may have a supply line to the front level valve but does not appear to connect to either of the airbags. Third, there only appears to be one leveling valve. Fourth, both front airbags appear to connect to the leveling valve but at different points rather than on the same "T".
So it may come down to how the exhaust air from the leveling valve is handled. We know we can exhaust the air via the kneeling controls.
Jim
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I'm now very close to the conclusion that manual controls and gages are the way to go here. The leveling valve is going to try to level the bus no matter what you do I think, and with a direct line it has the final say in the matter. The kneel function disables one part of that but if you use the raise position on the switch it continues to try returning it to ride height even while it is raising. At the very least the automatic controls will limit the range of leveling. And the bus now has far too many automatic functions. Almost like it has a mind of it's own.
So I've blocked the front end up under the skid rails and if it's dry tomorrow I plan to slide under and look at the level valve and the lines. Because the main lines to the front air bags are 3/8" it will not be possible to air it up as quickly with the 1/4" manual valves that I have. However I can minimize that by only using the smaller lines right around the valves. With this setup the auto leveling will be disabled. This is one time when I think it might be a good idea to remove the associated hardware and lines. If I look at it and think I see a different way I will let y'all know.
One possible way might be with a valve inline between the leveling valve and the air bag. It would need to be a somewhat fancy valve and I'm not sure there is just one that would do the job. Maybe a 3-way and two simple on/off solenoid valves. So the 3 way would divert between the leveling valve on one inlet and the air jack control on the other. I think it would have to be solenoid operated, powering up when the engine power comes on. Then the other two solenoid valves could add or remove air. But that basically means one 3-way and 2 solenoid valves for each air bag or each axle end. So 6 3-ways and 12 solenoids. That's likely to get a little expensive. But the upside is that no changes would be made to the OTR system, and the leveling system, being electrically activated could be automated rather easily. Or, the jack side of the 3-ways could be brought back to the manual valves and air gages. That actually is beginning to sound like the best solution.
Or maybe a hybrid with solenoids to vent the air. That way lowering could be accomplished quickly, and there would still be an air line to read pressure. Running 4 wires and four 3/8" tubes to the rear would be easier than eight 3/8" tubes, and cheaper. Maybe even enough to offset the cost of the solenoids. Go ahead and run 8 wires and if the supply solenoids are added later the wiring is already there and the tubes still feed the gages. That doesn't sound like too bad of a plan. If pressure side solenoids are expected, 1/4 lines could be used. If part of the install, 1/8" would be adequate. (and I have a big roll of that)
With that, if the bag is inflated beyond standard ride height (not unlikely), when the engine is started the leveling valve will lower it. If it is low it will bring it up. So the only thing needed when heading out would be to start the engine and by the time air pressure is up the normal ride height will be restored. It also will not interfere with the rear raise or kneel. The only real issue I see is that you would have up to six 3/8" solenoids powered up all the time when driving. Probably no more than 6 amps of current though at the most. Failure would mean reverting to manual control at that corner.
There is a possibility that the front leveling valve has separate valves on each line. That would allow some roll control. If that is the case they should be individually controlled. Does anyone have experience with those?
Jim
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Why not look at the Level Low system on Prevost VIP coaches and copy that - FWIW
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I would not set the system up to auto adjust to drive level when the key is in the on position as mine does that and I will change that so when I want to drive I will add a switch for when I am ready to drive .
my new coach has the all auto setting by hitting the button for level when camping but to me it works in reverse as it always starts the level cycle by dumping the air in the system . some times this is good but if I am way off level then after it has tried and failed then the on board compressor starts up to add air and it takes a lot longer then if it were to add air in the beginning .
the old simple manual push to add air and pull to remove air system on the old coach was so much faster and way simpler to use and to adjust for level . plus it never had a leak as it was so simple with no splits in the lines from the valves to the bags
dave
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Well first off there is no key on this bus, just the main power switch on the dash and the main disconnect in the battery bay. It would be easy enough to add another switch in a convenient spot.
The present plan has about 3 options though.
(1)-full manual leveling using air switches (valves)
(2)-manual with solenoids on the bleed side (purge)
(3)-manual with solenoids on both bleed and compressed air sides
The last two allow for automated leveling later if desired but that would come... well, later.
In all 3 of these options there is one common feature. A valve is placed in the air line going to the air bag. That's the simple version, it can get fancier as desired.
The purpose of the (selector) valve is to isolate the air bag from the coach's onboard leveling system. This has two advantages. It means the coach's original leveling system does not change in any way. It remains as the manufacturer designed it, which is generally a good thing. The second advantage is the jacking system can now disregard the OEM leveling system entirely, another good thing. This can be done as simply as by adding the most basic of on-off valves but a high flowing solenoid valve makes the most sense. It should be a Normally Closed type so that it doesn't have to draw power when sitting leveled. Typically these will draw well under 1/4 amp of current when activated which is no problem on the road and if one fails it will default to the jacking mode which is an acceptable fail safe.
Between the selector valve and the air bag is one or more "T"s in the line for the jacking system. This can go back to the driver's area to a manual leveling valve and optional gage (1) meaning that can be the only additional air line and it can be large to help with rapid leveling. The system can instead use an adjacent solenoid valve to bleed for lowering along with the aforementioned line for pressurized air for lift, allowing monitoring of pressure (2). This can allow quicker lowering if a high flow solenoid valve is used. A check valve with a 20psi cracking pressure on the outlet of the purge solenoid could be used to maintain air bag integrity, this should still allow lowering to the bump stops. Or, solenoids can be fitted for both air and purge (3). A gage line may or may not be added as desired.
In all 3 of these options the leveling operation is still manual but the 2nd and 3rd lend themselves to automation if desired and allow more options. For instance a master switch could be used for All Purge when setting up if the ground is flat and a low step is desired, allowing the bus to be dropped to the bump stops before leveling. Or perhaps purge only on the rear or front. Then any of a variety of leveling switches or devices could be used to bring the coach up to level. Maybe they have an Android app for that, who's to say. You might be able to level your coach from 3 states away. Not my concern.
I think this plan makes more sense than trying to acquire and graft in someone else's system with no idea how that is supposed to work. It's minimally intrusive, can use easily sourced components, shouldn't be too expensive, and is easily upgradeable. My initial searches indicate that acceptable solenoid valves should fall in the $10-20 price range when buying in quantity. Should be under $300 in costs plus fittings and tubing. That seems pretty low-buck.
Jim
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Dave, what brand auto level system do you have? Mine is made by Valid and can be programmed to auto-level by either first raising or lowering according to user preference. Many of the older powergear air levelling systems were a joint venture with Valid as well and most have the same programming capabilities. My system is highly configurable to just about any parameter, but the average user would have no idea about any of it, most people just push the button and forget about it.
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I have some more information about the bus.
First, the two front air bags are in fact "T"d together and fed by the white line coming out of the kneel controls panel (photo above). There is no other connection to that line, and the "T" is welded to the bracket the leveling valve is mounted on, making it easy to mistake it being connected to the level valve. It is not.
A 1/4" red line comes from the LH air bag into the Kneel panel. it goes to the 50psi pressure switch.
A 3/8" blue line runs from the level valve forward through the bulkhead. I believe it is the line that goes to the distribution block connected to the air tank in the left front under the driver.
A 1/4" white line runs from the level valve into the kneel panel where it connects to the bottom valve. We could really use an explanation for how that valve operates. My guess is that it is an air piloted 2 way valve and I suspect this will prove to be compatible with the system operation explanation, although I also suspect it has an internal bleed from the pilot line to the air bags. This would enable the slow rise after fast recovery.
So first off, the lines we need to access are available from the kneel panel and there is no need to go under the bus. Analysis of the kneel panel may provide more options for connecting the jacking system. For instance, hijacking the leveling pilot line may be all we need to do, although also hijacking the pressure switch may be an advantage for faster fill rates. Bleed can be accomplished through the PPV solenoid valve and the existing regulator will limit purge to 20psi.
I think we can do this with only one small 1/4" solenoid valve and some switches, maybe a relay or two. Pretty unintrusive to the original system too. So here's how I see it working:
Put a solenoid valve in the level line inside the panel. That shuts off the level valve and disables slow level control. Use a N/C valve so that when not OTR the system shifts to jack control automatically. Or, a master switch that lets you disable leveling OTR if you prefer. Or both.
Now to purge we power up the top coil of the PPV and exhaust the bellows as desired down as far as the bump stops, limited by the 20psi regulator.
Then we power up the bottom coil of the PPV and at the same time the fast recovery solenoid to lift the front of the bus. This may require a DPDT switch so that the two solenoids remain isolated. A diode could do the same thing. Or a relay. Provided the electrical power does not come from the 50psi pressure switch, full system pressure should be available for maximum leveling range. So, electrical switches, electric controls, upgradeable.
Now it also should be possible as mentioned, to hijack the level line. For this, a 1/4" line from that valve in the panel to a dash mounted operator valve with whatever air supply is handy (Bay door latch control supply?) would give manual control with no electrics. I think that's about as simple as it gets but I would not expect it to be fast.
Jim
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I have a test ready for tomorrow, using bits-n-bobs. Removed the level line and capped it, stuck another line on the valve and put a manual 3 way on it with a line to the quick disconnect on the front tank so that's all ready to go. If it works right I might be able to lift the coach off the blocks with the airbags. Find out about noon tomorrow.
Jim
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Dave, what brand auto level system do you have? Mine is made by Valid and can be programmed to auto-level by either first raising or lowering according to user preference. Many of the older powergear air levelling systems were a joint venture with Valid as well and most have the same programming capabilities. My system is highly configurable to just about any parameter, but the average user would have no idea about any of it, most people just push the button and forget about it.
the level system is a vintage 2000 H W H and works well but every time it dumps air to level first . but if I know it is a not a level lot I use the manual set up and do it myself by adding air to the part that is low and go from there . the system works ok but I like the bus nut way better
dave
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Of course it couldn't be quite that simple.
I did manage to get full excursion so that's the good news. Otherwise it was all pretty screwball. First, in order to hijack the leveling control line I had to shut off that valve it runs into. That's going to make control purely by air a PITA and while a 1/4" line will work it is going to be unbearably slow. I can't imagine running that size lines all the way to the rear. Wood blocks would be quicker. And the controls to the solenoids didn't react as expected either and it may take awhile to sort out what exactly is happening there. The PPV solenoid for instance wasn't real useful. It seems like is just shifts from pressure to exhaust which makes it no good for leveling. The fast recovery solenoid is good for raising, but only up to a point, probably the point where the 50psi pressure switch opens. Which means that has to be overridden somehow. I can probably sort that part out in the panel, at least I hope so but the 24v source is going to have to come from the dashboard area so that's another wire to run if a relay is needed.
A good wiring diagram would help. Unfortunately the ones in the tech bulletin are too fuzzy to read and as we know aren't correct anyway for this bus. The ones in the online maintenance manual all have the legend and some of the traces missing where the drawings were truncated so they aren't much help either.
I'm going back out to have another look, particularly at the circuit from the 50psi switch to the fast fill solenoid to see if I can find an easy way past that. Then I'll need a fast purge valve of some sort that I can open and close at my pleasure.
Still making progress, just not in a straight line.
Jim
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OK, not so bad after all.
Of note: some PO had screwed in the adjustment on the regulator to disable Kneel. It had the effect of setting a minimum air bag pressure that was close to normal ride height. I backed it off to the point where the regulator just starts to stutter. That seems about right or maybe just a small bit low. I haven't tested the kneel function and may find other issues there but I'd heard that disabling Kneel was common among fleet owners for liability reasons. So it may be fine.
Now for the fun stuff. Once the level line is disabled, jacking control is all electrical. No changes need to be made to the coach's ride control system. 4 wires run down to the panel are all that are needed I think, maybe another wire for the leveler solenoid.
On the terminal strip at the bottom of the panel are 5 posts, 4 of which are used. To raise the coach, a ground is applied to the left hand post and 28v is applied to the (bus) front terminal of the pressure switch. This will directly energize the fast fill solenoid and raise the front of the bus as high as it can go. You can stop by simply disconnecting. So a DPDT switch works here. It is fast enough that momentary-on will work fine. To lower, momentarily apply a ground to the second terminal from the left and 28v to the second terminal from the right. This will engage the PPV valve into purge mode and it will drop the front of the bus all the way down even after you remove power. The only way to stop it is to apply power to the fast fill solenoid. (which I think also applies power to the fill side of the PPV) So, the same SPST switch can be used for both, wiring power and ground to the center terminals and connecting the other four appropriately, 2 for lift and two for purge. Now you simply hit purge momentarily (spring loaded to center is what you want here or M-Off-M) , wait until it drops about where you want it, and hit fill. Then lift to level.
Doesn't get much simpler than that. I'll be ordering a common 1/4" solenoid valve and a switch if I don't have something handy. The only remaining question is how well it will hold the set level while sitting but it seems pretty air tight. I do plan to run a test where I set the level high and leave it though.
The rear doesn't look anywhere near that simple at first blush, but I've blocked it up and should be able to get at least part way in there for a look. Unfortunately there doesn't seem to be a handy convenient panel to work from.
Jim
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After some trouble getting a solenoid I found acceptable here is where I'm at. (Photo)
As you can see it's a push-on style which is convenient, just slice the tube and insert. The description said it is a 100% duty cycle but isn't meant to be on all the time. Whatever that means. Probably means at some point the coil will burn out but since the failure mode should be Off, big deal.
Next job is to find switched 28v in the panel if possible, or upstairs if not. Then find appropriate DPDT switches.
Jim
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Ran a 1/4" air line yesterday. I drilled a hole up into the air duct in front of the baggage door and fished a line up into the electrical panel by the driver. Two lines actually. I ordered some 5 conductor cable for the control wiring and will fish it through when it comes. So since I had enough air line on hand I fished that through first, cut the red line in the kneel panel (goes to the pressure switch) and connected that up using a push-on "T". Then I ran the loose end down into the service bay below and routed it over and up with the other air lines (having pulled the bay door control lines out, leaving the two lines running down the sides of the bus), pulling the slack up into the defroster area and attached an air pressure gage.
That leaves me some nice options. Because I have the manual air valves, I can "T" off of the gage line for a manual control as well as the electric controls. Slow but sure. And I'll be able to watch for leakage.
Next I'll add a ground to the new solenoid and clip a jumper wire to the 28v bus to air the system back up, check pressure, and see how well it holds air. The wire should come in a week or two.
I've also ordered a pair of 22ton pin type jack stands, and took a chance on a new Chinese supplier selling 22ton air/hydraulic jacks for about $50 each. I ordered a pair, so we'll see whether or not I just lit a cheap cigar with a hundred dollar bill. Should know in a couple of weeks.
Jim
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You can raise the rear of the DL 4 inches with a button on the left upper panel it only works with 100psi and over takes about 10 to 15 seconds for it to raise
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Yep, did that and blocked it. That might be a clue to the control system on the rear. I'll get a look at it once the jacks arrive.
I tested the new solenoid, the gage line, and the existing kneel and recover functions today, all worked as expected. Kneel pressure is just slightly over 20psi and standard ride height is at a bit over 60.
Jim
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Yep there are 2- Norgren valves back there it should be easy
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Finished the wiring for the switches on the controls for the front today and tested. It works about as expected with a few quirks.
Resumption of normal ride height is fairly slow and only begins after the door is closed and if power to the new added solenoid is turned on. I can't say if the solenoid restricts flow and slows it down, but it might. It's probably fast enough though.
Purge (lowering) is very fast and does not stop until the rocker switch is pressed in the lift direction.
Lift is relatively slow but considerably faster than the automatic resume. I will play with it some later, it may be that the kneel switch will do the job just fine but it is unpowered with the main switch off.
Also the lift position on the rocker backfeeds main power, so all the instrument lights come on when lifting. Didn't notice that from down at the panel. But it's not a bug, it's a feature!
Jim
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https://www.mcicoach.com/service-support/serinfo/serinfo12B.htm
It might be possible to talk to this controller with CAN messages and get it to set the height of each corner individually.
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Maybe that could be made to work for the newer buses, I don't think mine has the CAN bus.
If I have time I'll try to get out the jack and jack stands today. I need to decide which end to work on, as the front leaks down. So, do I work on making the front end airtight, or do I work on the rear controls? Hard to decide.
Jim
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How do you make that work with the existing leveling valves ?
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Read the thread, it's a work in progress.
Jim
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I've changed my mind about how to do this because a mechanical system will have no issues with leak-down ever. Semi landing gear are pretty good jacks with 4 times the needed lifting capacity so I am installing a set of three 17" travel Jost gear in a tripod arrangement, located at the front and rearmost bay bulkheads and anchored to the axle subframes. The front one is now installed except for the trim. I should be able to test it this week sometime.
In operation I expect to use the air ride suspension to drop the bus onto the bump stops and bring it up nearly level, then extend the jacks, take up the load, and finish leveling. The return to ride height at departure should eliminate any risk of driving away with jacks down, as well as making retraction an unloaded operation and therefore easier. I think it should be pretty easy to add limit switches for powered operation.
Jim
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The front one is now installed except for the trim. I should be able to test it this week sometime.
Looking forward about this. Those things are expensive new and something likely to be available in the used market. Personally, I have not had any trouble leveling bus sufficiently to our likings. Some may need zero degrees flat, we aren't so particular. I use the multi-level wood ramps for leveling and it has worked for us. Some desire push button, fine with me. Still interested in learning repurposing the truck jacks.
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Thanks Don, glad there is some interest. I put the cushion foot on today, it had to be removed to avoid cutting a larger hole in the floor and I modded it so it would bolt on with ten 1/4" serrated head bolts. They don't see any of the load, just secure the retaining collar to the foot. Also finished the motor adapter for the gear reducer and I'll slip that on the shaft when I go back out and look for a simple way to tie down the motor. After the electrical check and adding oil. Next I have a little mig welding to do which I hope to get done today and then I have the trim work on the bottom of the bus which includes reattaching the end of the center stringer around the jack. I'm putting off photos until after that's done.
I like these Jost gear. At just under $300 each they are cheap. Well, not compared to wood blocks but compared to other landing gear. The gearmotor to drive one will run into some money of course but there's no reason not to crank them down manually or as was suggested, with a battery impact until they touch. And there are surplus gearmotors out there if you know where to look. After my test I'll know more about what can work and I'll go shopping. You can chain drive 'em if needed, and there are also taper hub sprockets that will work on a keyless shaft. So a lot of possible options if you can do a little rough fabricating.
You could probably find something used, but watch the travel and overall height. You might save anywhere up to $700 that way if you find a real deal. But sometimes it's better to just buy something new that will work correctly than trying to adapt something that may be worn out. And it's also nice to work with clean parts.
Jim
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Keep all the greasing points either accessible, or run hose to a centralized location.
They get real nasty as the lube dries out in 'em...
Happy coaching!
Buswarrior
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I've had the caps off and these have about a pound of very sticky grease in the gearbox. That should come close to lasting the lifetime for my use. It has 2 zerks, top one to the gearbox, lower one to the slide. Both should be fairly easy to get to. Might need a longer hose on the grease gun but otherwise I think that'll be OK. I'll pay attention to that when I mount the gearmotors though.
I got most of the welding done yesterday except the bottom trim. Gearmotor is tested and hung on the shaft and the cushion foot is installed. Used stainless wire to weld the angle brace to the bulkhead and standard MIG wire to weld it to the subframe. One more bulkhead weld to do and then sealant and paint.
Well, off to work.
Jim
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if in the future you intend to grease, make sure it is compatible with what is already in there.
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Pictures!
I still have to apply seam sealer, I'm using Permatex Ultra Black gasket maker which is fairly serious overkill but at least it'll stay put. Also I'm looking at how to best install limit switches.
Ops check: N/G
The speed is acceptable if somewhat slow at 3.4 seconds per crank rotation but the 1/2 hp motor isn't nearly ballsy enough. Which means that gearbox isn't either. Time to go scrapyardin' for a suitable replacement. Probably something in the 2hp range would be my guess. Which means I can forget about using my surplus inverters here. Oh well.
Jim
Oh, and thanks for the advice on the grease. I figure any good EP grease is probably good enough. I made up the shortage in one unit with some black lithium grease which I've had forever and needed to use up.
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Does that landing gear have a two-speed crank? If so, are you sure it's in the low gear? If it's in the high gear it might be the cause of the problem the motor is having.
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Oh baby, what Richard asks...
If there's any lifting at all, as opposed to running them down and then dumping the suspension to load them...
You'll be wanting low gear, or a way to readily click it between high and low.
Happy coaching!
Buswarrior
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You just need to get the gearbox that semi trailer jacks use to give the Motor more mechanical advantage.
You only have the bare jack, typically they come mounted on a trailer with a two speed gear box that drives both jacks and the hand crank is attached to that gearbox. (Richard eluded to this)
The handle does NOT drive the jack directly like you are trying to do with that gear motor. There is no way you could lift a loaded trailer with the handle direct on the jack. That is why they have two speed gearboxes, high gets the jack to the ground and then low gear had better be working to do the lifting or you have to dump your air suspension to get your truck out from under a loaded trailer.
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Oh baby, what Richard asks...
Buswarrior
Not sure if I asked it correctly...
But I know that trying to crank up a trailer that is stuck in high gear is a losing proposition. Not easy for a driver, certainly not easy for a 1/2hp motor.
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Well, that's certainly a valid question, but I never had any intention of running these by hand. And the reduction type units are taller. I bought three right hand units. No reducer. The idea being to do the reduction in the gearmotor. This test unit has a 100:1 reduction ratio, meaning it takes 3.4 seconds to make one revolution or about 18 rpm. Takes 4 cranks per inch of travel, so a minute to go 4-1/2". I do have a 1000:1 gearbox I can try just for a test but it's really going to be too slow for practical use. (Can you imaging spending 15 minutes to jack one corner?) It looks like the Jost gear reducer is very close to 10:1, so my requirement is probably going to be less than that. Anyway that should be a usable test. Provided that works, at an overall reduction of 100:1 I could expect to need a 5hp motor since that's 10 x 1/2hp. That should bracket the range nicely.
In messages with the Chinese manufacturer of jacking screws I was quoted a 3hp motor required to get something in the acceptable speed range. Because I had this test unit I decided to try it just to get a data point. Before this is over I may go back to that vendor for a price quote. However I suspect there may be other more competitive vendors and there is also the surplus market to explore.
It will be relatively simple to add the 10:1 unit for another test. I'm also relatively sure these light gearboxes will never hold up to this application so a test is all it will be.
IF the 1000:1 reduction works with the 1/2hp motor that does raise the possibility of using it with automatic controls such that on parking I could throw a switch and walk off and forget it, coming back in 15 minutes to a leveled coach. That could be workable. They are reasonably quiet.
The input torque required for the rated 62,500lb lifting capacity is given as 1000 ft/lbs. So about 300 ft/lbs for this application. That means a fairly robust final stage on the reducer. A sprocket drive can give me about a 5:1 final ratio I believe, depending on the diameter of the driven sprocket. That would reduce the gearmotor output torque to 50 ft/lbs which is considerably more manageable. Maybe I'll go ahead and run that second test today.
Part of the problem is that although we think of worm drive speed reducers as being incredibly robust, in reality they are not, due to having a small area of contact on the ring gear. Wear and tooth breakage become real issues under heavy loads. The diameter of the ring gear has to increase rather dramatically as the torque requirements go up, and in the 300 ft/lb range it probably has to be around 5-6" making the case fairly large and heavy.
In retrospect getting the reducer units and paying the extra would probably have been advisable.
Jim
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OK that test was successful. The motor didn't sound like it was working at capacity but I'll have to stick an amp clamp on it to see what the current draw is and that will tell me how close I am to a full load.
It is very slow, but like I said if run as an automatic leveling system that shouldn't be very objectionable, and the big benefit is the ability to use my 900w inverters and switching relays that I already have for directional control. A current limiting relay could be used instead of limit switches also.
Jim
Just checked, running load is 6 amps, FLA is 7.2A so it's running at 83% of full load, a comfortable margin and just about where it should be. I think this speed should be acceptable. I can always upgrade later to 3600 rpm 1 hp motors without changing gearboxes to cut the leveling time in half.
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I'm now working on the major truss, the one at the rear that will support the side jacks, and I've had more time to think things through. I've reached the conclusion that the drive system on the front jack is usable but not very convenient. One of my options is to consider the use of 3-5hp motors. On the gearing side, it would appear that a 5hp would allow the use of about a 100:1 reduction ratio, increasing the speed by a factor of 10. This means that instead of taking 10-15 minutes to level the coach it would take 60-90 seconds which is much more in line with what we expect to see. Even allowing a 50% increase for the additional weight of the build-out that doesn't go much over 2 minutes.
On the power side, I believe this means about a 30 amp draw at 220vac but my 8kw genset should be able to handle that load, the key being not to try driving more than one loaded jack at one time. It also means careful management of power when running AC. But I think that is feasible.
This week and next I'll be working to complete the major truss, get it installed, mount the jacks and trim out the installation. Then it's off to the scrap yard with me to see what sort of gearmotors I can find.
Jim
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Be careful you don't leave yourself stranded high and dry should your generator ever crap out on you. If you are relying on the 240v from your generator to run the motors, what will happen when you're out somewhere and your generator dies? Finding a 120v outlet would be easy, but a 240v one will be more difficult.
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3 to 5 hp motor could trip breaker on 110 volts.
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How often would you need to drive a loaded leg?
In practice, evaluate the terrain, lower legs freely under the air suspended bus to get 'em close, estimated to be where they need to be to be level, deflate air suspension, legs touch down in turn, coach is level.
Reverse method to raise free legs?
I'd be letting the air suspension do the lifting, let the gear motors just freely position the legs?
Happy coaching!
Buswarrior
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I think BW has it figured out, and in more ways than one.
Using the air ride to get to rough level is likely to be the quickest way of doing it. And it will almost always be able to unload the jacks. The exception would be when changing a tire.
I will probably be looking for 3 phase motors. They are generally capable of higher torque, and reversing is easier. Used, they tend to be cheap. But of course that means a VFD to drive each one. Still, there are VFDs that can use 110v and output 220vac 3 phase (how that's possible I don't know) and remote switching can be used for on/off, reversing, and speed control. Some are capable of approaching 150% overspeed under light load which could be handy.
I don't know yet what the unloaded amperage draw might be, but with soft start (from the VFD) it could be possible to drive an unloaded jack with the output from one of my 0.9kw inverters. If so that'd be an easy method of positioning so it's worth checking it out. And as BW suggested, level with the air bags, run the jacks down until they hit, and when leaving use the bags to lift the bus off the jacks. Later on of course I hope to be able to add a large inverter but as those are expensive, bulky and heavy I'd like to put that off for awhile.
Also, because I have a purge on the front and hope to add them to the sides, I hope to be able to drop the bus down to the bump stops before leveling it. (and the purge can be stopped at any point on the way down) Depending of course on how much of a slant there is. So just the way the bus rises up from the kneel position before moving off, the idea is to do the same at the rear. Meaning that on a reasonably level surface the bus can actually be moving while the jacks fully retract, and if there is a malfunction it can still be driven. Just how well that all will work remains to be seen of course, but I think the basic plan is solid.
Jim
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OK my 2 cents here (and for what it's worth. Add $5 to it and you might be able to get a cup of coffee at the local truck stop!)
I'd use little air actuators on each leveling valve like Setra did so you can raise the bus about 6" all the way around before leveling to give you plenty of "wiggle room" then I'd use the 2 speed gear boxes that are on most semi trailers for your jacks and it theory if needed you could use one of today's cordless impacts to drive the jacks!
Or use an air impact to drive them.
;D BK ;D
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or just use the air bags in the coach to do all the leveling
works on the coach I have now and the M C I that I sold
dave
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Here's a shot of the major truss. It should go in today if there are no problems. What you can't see in the photo is that the top stringer is doubled, as it is offset to fit into the recess in the bulkhead.
What I was thinking was that I don't want to carry around a set of steps, so it made more sense to drop both ends as far as possible before leveling. Oh, and the torque requirement on those jacks is 1000ft/lbs at full load. That comes out to about 300 each on the bus. With the 10:1 factory reducer that gets dropped down to where the impact wrench could handle it I think. Worth a try anyway.
So sitting in the driver's seat watching the levels, I'd hit the purge valve(s) for whichever end is higher and bring that end down to the bump stops. Then if that is the rear, put some air back in the low side to get level side to side and then drop the front with the purge and stop it when it gets close and then level it. Then run down the jacks. If the front is highest, drop it to the bump stops, then drop the rear to hit level end-to-end, then level side-to-side, then lower the jacks. That way the entry will be as low as it can go and there should be no need for an extra step most of the time.
Now granted, there is no reason why that method won't work with using a battery impact to put the jacks down. And that makes a lot of sense. Plus when you go to drive away the bus will come up to standard ride height by itself and lift the jacks off the ground most of the time. But I didn't buy the jacks with the 10:1 boxes, and I planned all along to use gearmotors. Might as well stick with the plan. The only real variable is what gearmotors to use.
Jim
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Installed the truss today and got the four top bolts in. I'll try to get the bottom two in tomorrow. Here is how it fits: The rear bulkhead is pretty thick stainless and has a 4-1/2" channel near the top that is 1" deep. The truss has two top stringers made from 1 x 2 x 3/16" rectangle tubing welded with a 1/2" overlap and then there are spacer blocks below that so that when the doubler on the top stringer goes into the offset the blocks hold it to the top of the offset, then four bolts go through the top stringer and the doubler and into the suspension subframe which is formed of 3/8" thick steel.
The ends of the bulkhead are welded into the framework of the body and the top forms part of the floor support system so it is very tightly tied in and the top 6" or so of the bulkhead is pretty stiff, especially out near the ends. The recess allows the load to be transferred to the doubler, from there to the top stringer, and from there to the downlegs that the jack is bolted to.
In addition, the truss itself transfers loading from the six 1/2" attachment bolts and the central section of the recess out to the jack mounts. To resist twisting, the jack mount sections will have four 5/16" bolts per end clamping it to the bulkhead panel, and the floor trim will include a containment collar to secure the lower end of the jack and prevent lateral movement in two axis. The side bracing and floor will add to the rigidity provided by another stringer running along the base of the bulkhead and bolted to the suspension frame in two places.
I used the leveling jacks to lift the truss up into position and it fit like a glove. Probably weighs somewhere in the neighborhood of a hundred pounds, but I think along with the support provided by the bulkhead that it will do the trick. The minor truss looks beefier, but I don't think it is any stronger. Still there is some risk with any cantilevered construction. The true test will be to see how solid it feels with all the tires off the ground. Probably won't be to that point for another couple of weeks.
Jim
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So I went to the local scrapyard and scored three gearmotors yesterday which I do believe I can press into service here. Unfortunately I doubt I can use the motors but the gearboxes were well worth the $75 each I paid for them. (a new gearmotor to serve this purpose could easily cost over $2k each)
The center one is a SEW/Eurodrive with a 541:1 ratio and a 1/2hp motor. That one has a hollow shaft and can hang on the input of the front jack, and MIGHT have enough power to lift the bus without help. If not it will at least give me another datapoint. I plan to swap that motor for a 1-1/2 to 2hp 3450 rpm one which will double the speed, effectively cutting the ratio to 270. If it is capable of lifting the bus as it is that will mean I can use a 1hp replacement motor and it will help me in sizing the rear ones as well.
The other two gearboxes are 80:1 and 60:1 respectively, have a solid shaft output, and will need a chain drive, meaning additional reduction there. With a 3:1 and a 4:1 chain drive I can achieve a 240:1 ratio, nearly matching the front so the same hp motors but in 1725rpm should apply.
For a perfect match the chain reduction would be 3.375 and 4.5 respectively, certainly feasible with available sprocket sizes. Rather than hanging off the input shafts directly the boxes will have to hang alongside, which is why this had to be done before the waste tanks.
The other photos show the side jacks in place mounted on the rear or major truss. Although in the photos it may look a bit spindly, it is solidly attached to the rear suspension frame and the bulkhead and tied into the side frames as well and is designed to transfer load directly to the upper offset of the bulkhead so I think it will hold up the bus. It is built along the lines of a bridge truss design.
I found my cord to tie into the 3 phase and will be testing 2 of the three motors later (one is 440v only which I don't have) and then I'll need a bore adapter for the eurodrive but once I have that I can proceed to the next test. In the meantime, I have used a ratchet and extension to take some load on one of the side jacks but I don't have the tire off the ground yet. In hindsight, the 10:1 built in reducer would have been a good thing but there really wasn't room for it in the front. It would have greatly simplified things at the back though.
Jim
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Are you guys still interested in this? If you aren't that's OK, just one less thing for me to do. I do realize it's drifting into the more arcane part of things what with gear ratios and current draw and whatnot. Sometimes it breaks my brain to think about it.
But anyway, yesterday I ordered sprockets for the two side jacks. I was fortunate enough to find what I needed on ebay and was able to get all four for around a hundred bucks so that was a pretty good deal. The chain I have enough of. It's motorcycle chain so I may have to thin the teeth a little but that's easy to do. It's 40 pitch which has a 1/2" spacing between the pins. For this application I think it'll be fine although nominally it might look a little on the skimpy side. It has to handle about a 750 lb pull and I think the rating is about 525 lbs. I found two 60 tooth sprockets with a 1" hub and those will fit the available space. For the reducers I found one 13 tooth 1-1/4" bore sprocket for the 60:1 reducer and a 17 tooth 1-1/2" bore sprocket for the 80:1 reducer. That should put me close to 280:1 on both sides. The front is 541:1 with a 1725 rpm motor so if I switch to a 3450 rpm motor it will double the speed. That is roughly equivalent to cutting the ratio in half which would be 270:1, meaning that the front and side jacks will then be running at the same speed.
The question then becomes the horsepower requirement which based on earlier testing should be no more than 2 hp per motor and the next test using 3 phase power will nail that down more closely.
Now then, 3 phase power on a bus you ask? Yes well, things have gotten more inexpensive you see. Today you can buy a VFD drive that will run on 220vac for about $65 and power a 2 hp (1.5kw) 3 phase motor so it's reached the point of affordability. And that drive is easily reversed with an external switch and also has some pretty sophisticated electronic controls. Like soft start which we find useful. It may even be able to run the motor at a higher speed under no load conditions. So a simple up/down switch on the console ought to do the trick. It also lends itself well to an automatic leveler that can be added later.
To power that VFD (and at the 1/2 hp level they can run on 110vac which can be very useful sometimes) all that is needed is a 2kw inverter. You can buy those with a sine wave output all day long for about $35 each, meaning the jacks can run on battery power if needed. Or the generator, or the shore line. That takes care of that.
The motors may be a bit expensive but there are quite a few available for under $100 so hopefully I can find the right combination of rating, shaft size, speed, voltage, mount type, and size in that price range. If not, the cost of new is not prohibitive. Even so I think I still have a pretty good chance of keeping my total cost under $2000 which is exceptional for such a robust leveling system.
Jim
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Jim, very interesting knowledge. I am impressed. Keep it coming :^
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OK, I'll keep going with it. One thought I did have if anyone wants to try this, you should be able to run it with a garage door opener. I know that sounds far fetched but all you'd need is a jack with the 10:1 reducer, a 1/2 hp opener, and 100:1 reduction from the motor to the jack. It'd be slow but it'd work. A typical opener has a 20:1 reduction and a 10 tooth drive sprocket meaning the driven sprocket would need to have 50 teeth. 10x20x5=1000:1
It'd be a light duty drive of course, but also light and inexpensive. The heavy part of the reduction would be at the jack itself, reducing the torque requirement from 300 ft/lbs to 30 and then the chain reducing it further to 6 ft/lbs at which point the plastic gears of the opener take over. At the motor the torque requirement is around 4 inch pounds, plus losses. The only reason I didn't try this approach is because I didn't think of it.
Jim
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Keep documenting the build.
The silent viewers will thank you, if they ever meet you in person out there somewhere.
Happy coaching!
Buswarrior
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I'm enjoying reading about it. Makes no difference if I'm going to do the same on my current bus, I'm learning from your efforts and enjoying the play-by-play.
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OK then as long as someone is benefiting from it. Not much to do today as I'm waiting on orders to come in. My next step is to make a sleeve to mate the front gearbox to the jack. I ordered some 1-1/2 x 1" round tube and I will need to cut keyways in it. The outer one is no challenge, I'll just clamp it in the mill but the inner one? Well I don't have any keyway broaches so that one takes some creativity.
The tube wall is 1/4" and the key is 3/16" I think. Half that in the sleeve. So what I'm going to do is to slot the tube, position the key in place, and then make some heavy tack welds on top of the key from the outside. That will lock it in place and restore the integrity of the tube. Clean up the welds so it'll slide into the reducer, and job done. It won't be possible then to replace the key but that should never be necessary anyway. A snap ring goes in the bore of the reducer so the sleeve can't escape and it's a slip fit assembly. The bracket to restrain rotary motion is all that's required to mount it.
Now overall length may be an issue once a 2 hp motor is attached and probably will be. This gearmotor is really serious overkill. But I can resolve that by swinging the motor end up to the top of the bay and anchoring it up there, more or less parallel to the floor which will also leave more generally usable space below. Photos to follow at some point.
Jim
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The photo below shows the results of yesterdays labors. In the second photo you can see my method of attaching the key for the inner bore. Not pretty but plenty strong and won't be visible. This piece allows me to hang the gearmotor off the shaft of the front jack, which is today's objective along with measuring amperage draw to determine the horsepower requirement.
Jim
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Good progress today. Photo 1 below shows the gearmotor attached to the front jack. Pay no attention to the ratchet strap. This is not the ratchet strap you are looking for.
No actually I haven't decided if the motor will hang or be supported horizontally. The good news is that during the test run the motor drew less than 1 amp at any time and never sounded like it was under any significant load. (ain't 3 phase great) So I ordered a hopefully more sensitive amp clamp and will test again later. Since the full rated draw at 220v is 2 amps it's just possible that a 3450 rpm 1/2 hp motor will run it. But I'll wait for the new meter. My old one really isn't sensitive enough to say for sure.
2nd photo shows one of the rear jacks. I really didn't expect to get the drive mounted today but there you see it and I believe it will work well. I will likely add a strap tomorrow to prevent twist just as a precaution but it is ready to test. The other one is waiting on a sprocket to arrive but I may go ahead and mount the gearbox. I also need to come up with a motor for that one but I think I may be able to adapt a C face end bell off one onto another to get something that will bolt up and work. More fun tomorrow.
Jim
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Pretty impressive. How much total do the three weigh?
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Oh they aren't light. I haven't weighed anything yet but probably about 50lbs each, plus the weight of the jacks, plus the weight of the trusses. I figure the net is in the neighborhood of 300 to 400 lbs, maybe a bit more. I'll agree I should be weighing what I install, but it won't make any difference I'm going to install it anyway. And the gross gives me quite a lot of leeway so I'm just not going to worry about it too much.
If I was though, I'd go the garage door opener route. Jost are one of the lightest weight landing gear already but they are also made in aluminum, at about 27 lbs each. So that, along with the garage door opener would drop the weight down into the 150-200 lbs range if the side jacks were mounted inboard. I think.
Jim
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I admire your conviction on putting levelers on as it is a pretty big project, time, materials, and $$. Just have to ask, is it really that important to you to have this sort of configuration? I've used a set of drive on ramps when I can't get a flat enough place to park. Works for me and a whole lot less complicated and costly. The ramps do consume bay space but not enough to be of any concern.
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Don you are right that would be much simpler. But once you have onboard leveling jacks you never really forget how nice it is. I took a hard look at using the airbags for leveling, even spent a few bucks on it. But, on my last RV which was a 32 ft Coachman I outfitted it with a hydraulic system using surplus parts and spending probably around $400-500 doing it. And that worked really well for the cost plus it was very handy to have onboard jacks. But it wasn't long before the cylinders began to leak down overnight and it had to be leveled twice a day. I could see the airbag system was going to go the same way. Believe me, I didn't want to spend 2 grand on the system, and there are other things I could spend the money on, but in the end it is something I will use every time I drive the thing, and in between it will stay put. Both fairly important considerations to me. Like I mentioned I could have kept the cost right around $1000 with just the jacks and cranked them down manually. I might even have found them used for half price, and that would be well worth it. But leveling at the touch of a switch on a cold wet dark night from inside the coach after a long hard day? How do you really put a price on that?
Another thing is that getting the coach perfectly level with blocks takes quite a bit of skill and practice and I won't have the chance to develop that skill before I need it dead level in order to build out the interior and run the plumbing. Especially important since I hope to do an almost totally gravity draining system. With these jacks it's something that anyone could do easily with no real training.
So I'll spend 4 times what my hydraulic system cost. In return I will have a far superior system that can handle many times the weight and is much more stable. I've decided I can live with that. Plus if I need to get under the bus or change a tire it's only a very minor inconvenience to lift it up on the jacks and there's absolutely no need to carry around those 20 ton bottle jacks and jack stands. I think that's how I justify it Don, Just a matter of priorities. And it's one of those things that has to be done first or not at all.
Jim
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So today I tested the passenger side jack and it works quite well, though it is louder than the front one. Possibly because of the brake on the motor. Didn't need that but left it on anyway. It's a 1 hp 1725 rpm motor. Still really slow but faster than the front one. I can see an auto-leveler in my future.
https://www.bananarobotics.com/shop/Tilt-Sensor-Switch-Module?gclid=Cj0KCQiAhZT9BRDmARIsAN2E-J3d8pJRZmjbV_o7RjE3qqnVUwcCJTCNMvQ_DyAW5QedWRGBJH4KO8waAkgJEALw_wcB
https://www.electronicproducts.com/tilt-switches-a-new-angle/#
https://www.walmart.com/ip/Angle-Sensor-Module-SW-520D-Golden-Ball-Switch-Tilt-Sensor-Module/885745009?wmlspartner=wlpa&selectedSellerId=571
I believe one of these sensors could be tied to the VFD ON command terminal. Seems like a cheap and easy solution.
So anyway, using my old standby amp clamp it looks like this motor was drawing maybe 2-1/2 amps under load and has a 3 amp FLA rating. So well within limits. That was with the rear wheels off the ground. I'll test again once I have the new meter. One thing throws these numbers off a bit, I am using a 15 hp idler motor to generate my third phase here at the shop so the phase angles aren't optimal and 2 legs read higher than the 3rd one. With a VFD the amperage readings should be lower. My total power usage for this motor based on my readings today would be about 1200 watts.
Anyway I made up the extra brace and installed it. Also cobbled together a motor for the other side. It turned out that the end bells were interchangeable so I just swapped them and with a little cleanup it all bolted together. Great, no more expense there. The sprocket came in and it had no keyway and no setscrew but I did find a suitable 5/16" diameter roll pin so I drilled straight through and pinned the sprocket to the shaft. (Using my hand drill. Try that one on for size sometime on a 1-1/4" shaft.) Swapped the mounting plate position and the vent plug location and set it into place atop 5 two-by blocks and marked for the slots. On this side I had to cut off the shaft on the jack so the sprockets could be lined up close to the jack.
Next I get to lay out and cut the slots in the diagonal body strut which allow the chain to be adjusted, and that's a tricky job, but I'm cutting the slots parallel to the struts so as not to overly weaken them and the nut plate is a 3/8" x 1-1/2" stainless strap that ties both mounting bolts together, adding some strength back in. (had some stock left over from another job) Shouldn't ever cause a problem.
I think I'm going to need limit switches.
So next I get to cut those slots. Oh joy. Well I've been goofing off long enough, back to work.
Jim
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Two steps forward and one step back. I broke a shear pin and now I have to pull the top off the last jack to replace it. Well, these things happen. Luckily I gained some useful knowledge in the process. First, I now know that when the jack reaches a stop the motor isn't going to slow down. Well that's both a boon and a bust with 3 phase. OTOH the current rise is rather dramatic, something on the order of at least 8X before the pin gave up, and that should make it possible to use current limiting in the VFD to stop the drive when the jack reaches the end in either direction. Testing will tell how well it works to restart it the other way, but in a worst case I might be able to override the current limit.
(A quick and dirty estimate shows a torque approaching 2500 ft/lbs being applied to the 1" shaft of the landing gear and a pull of almost 6000 lbs being applied to the chain at the point of failure.)
So that part is good. And I've now tested all the mechanical bits successfully. And the jacks have adequate travel to lift all wheels off the ground which is how it is sitting now. I'll put a jack stand under it before I pull the cap off that jack that needs to be serviced just in case, since my fingers will be in the gears. And add a link to the sprocket chain, and add the side brace.
Then I think I'm going to take a break from this part of the build and level up the bus nice and accurately. Probably is no more reason to address this thread until I start working on a purge for the rear airbags, and the electrical drive and controls might be better located in a new thread.
However I do feel like the air purge belongs here especially since that's what this thread started off with, and the plan is to purge and drop both ends to the bump stops on arrival at a site, and then use the electric jacks to level the coach. Most times only 2 jacks will be required to achieve level.
Jim
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Here is the next episode:
https://www.busconversionmagazine.com/forum/index.php?topic=35152.new#new
The build thread is here:
https://www.busconversionmagazine.com/forum/index.php?topic=34360.30
Jim
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Jim,
This story has been going on nearly as long as COVID-19 with about the same progress toward the finish line. ::) You get mucho kudos for your passion for this feature, obviously high on your wish list.
In the beginning, functional specifications weren't mentioned; specifically, how much range are you building in?
Why does the typical solution of valving the existing air bags not satisfactory?
Did you consider an auxiliary air bag system?
I know you well enough you will have a workable leveling system but personally it seems like a lot of energy going into this single feature.
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Yes Don, you are right to ask those questions. But first bear in mind that I am on the 5 year build plan and some things just take time to get them right. So why not air? Primarily because air suffers from the same problem as hydraulics, in that they have a tendency towards leakage. This is easily overcome in a running system but in a static one not so much, and from experience I can tell you that it isn't so much fun waking up with your head downhill and then leveling the RV twice a day. There is a rumor going around that an air system can be leak free but that's never been my experience and I'm not basing my future happiness on my skills at relentlessly chasing that elusive goal. Plus the mechanical system is more reliable/safer as a maintenance jacking system. No concerns about getting under the bus in other words, as it isn't moving.
As features go, I'd say it is as important as say, a solar collector array, and about 1/4 the cost, maybe less. So as a personal preference it isn't that hard to justify. As for the work, well I happen to be very skilled in those arts so that wasn't any great challenge. I simply threw together a workable solution from available parts. And that is also why I didn't start with the specifications, as those were going to change and evolve during the build process. Consider for instance the final gearmotor choices vs the initially quoted motorized Chinese screw jacks. Either would have worked but these cost less, were more easily available, are weather protected, mounted more easily and take less power to drive. I believe the full travel distance is 13-3/4", and the feet do protrude slightly when fully retracted but not enough to scrape on speed bumps. Even Florida State Park speedbumps. That's enough travel to lift the wheels off the ground. Even more height can be gained with blocks and I believe a 6x6 will fit.
BTW, I did consider using the airbages for leveling. In fact I bought valves and such to do it and had modified the front kneel controls to allow that. I was ready to look at the rear as soon as I had the bus on jackstands. But you know, a curious thing happened. I realized that onboard jacks would be better than jackstands and matters just evolved. Now, I will be using the air controls for leveling, and in the following way: Upon arrival I will purge the air bags to drop the coach down to the bump stops. Then use the air to level it up roughly, and then switch on the automatic leveling system which I haven't designed yet. That is the final phase of the mini-project, coming up with some sort of a controller that can extend the jacks, level the coach, and shut off. I have plenty of time to develop that part as it is the least essential part of the system.
Jim
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Jim, keep up the good work. I am very interested in how everything turns out.
Jared
Are you guys still interested in this? If you aren't that's OK, just one less thing for me to do. I do realize it's drifting into the more arcane part of things what with gear ratios and current draw and whatnot. Sometimes it breaks my brain to think about it.
But anyway, yesterday I ordered sprockets for the two side jacks. I was fortunate enough to find what I needed on ebay and was able to get all four for around a hundred bucks so that was a pretty good deal. The chain I have enough of. It's motorcycle chain so I may have to thin the teeth a little but that's easy to do. It's 40 pitch which has a 1/2" spacing between the pins. For this application I think it'll be fine although nominally it might look a little on the skimpy side. It has to handle about a 750 lb pull and I think the rating is about 525 lbs. I found two 60 tooth sprockets with a 1" hub and those will fit the available space. For the reducers I found one 13 tooth 1-1/4" bore sprocket for the 60:1 reducer and a 17 tooth 1-1/2" bore sprocket for the 80:1 reducer. That should put me close to 280:1 on both sides. The front is 541:1 with a 1725 rpm motor so if I switch to a 3450 rpm motor it will double the speed. That is roughly equivalent to cutting the ratio in half which would be 270:1, meaning that the front and side jacks will then be running at the same speed.
The question then becomes the horsepower requirement which based on earlier testing should be no more than 2 hp per motor and the next test using 3 phase power will nail that down more closely.
Now then, 3 phase power on a bus you ask? Yes well, things have gotten more inexpensive you see. Today you can buy a VFD drive that will run on 220vac for about $65 and power a 2 hp (1.5kw) 3 phase motor so it's reached the point of affordability. And that drive is easily reversed with an external switch and also has some pretty sophisticated electronic controls. Like soft start which we find useful. It may even be able to run the motor at a higher speed under no load conditions. So a simple up/down switch on the console ought to do the trick. It also lends itself well to an automatic leveler that can be added later.
To power that VFD (and at the 1/2 hp level they can run on 110vac which can be very useful sometimes) all that is needed is a 2kw inverter. You can buy those with a sine wave output all day long for about $35 each, meaning the jacks can run on battery power if needed. Or the generator, or the shore line. That takes care of that.
The motors may be a bit expensive but there are quite a few available for under $100 so hopefully I can find the right combination of rating, shaft size, speed, voltage, mount type, and size in that price range. If not, the cost of new is not prohibitive. Even so I think I still have a pretty good chance of keeping my total cost under $2000 which is exceptional for such a robust leveling system.
Jim
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5 years? Hopefully you don't lose interest by that time. So common here. Enthusiasts just disappear.
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Thanks, I will. It's just that I've had to switch off to replace the engine in my MG and I sort of slow down a bit in winter. But I've been looking at VFDs and have one picked out that is usable it's just that it's a panel mount and I'd rather have a surface mount. That plus I've been working on the inside bulkheads. But I'll get back to it once I order the controllers.
For now they are working quite well though, I leveled the bus up using shop power and it's sat there like that ever since. The jacks have all sank a couple inches into the gravel but the bus is still level. I have some pads I got from my friend who runs a waterjet which were some drops off a job. 1/4" thick steel in an 18" diameter disc. Those will spread the weight nicely but I wanted to see what the feet would do. Now that I know, I will use the pads for soft ground most of the time.
Jim
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Have you tested your display ideas in the dark?
These things have a bad habit of reflecting in the wrong places...
Even the OEM's are making a mess of this topic, sticking them in wherever expedient...
Happy coaching!
Buswarrior
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Appreciate the tip BW. When I get to that point I'll be sure to pay attention to it. But that won't happen for awhile. Probably after the weather gets warmer, since I'll have to establish control wires from the jacks up to the driver's area on the left, and per your suggestion I'll add a switch to kill the lights. Thanks.
Jim