Author Topic: Leveling revisited for MCI 102  (Read 120 times)

Offline Jim Blackwood

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Leveling revisited for MCI 102
« on: October 12, 2019, 07:11:46 AM »
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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Offline richard5933

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Re: Leveling revisited for MCI 102
« Reply #1 on: October 12, 2019, 07:20:52 AM »
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.
Richard
1974 GMC P8M4108a-125 (Custom Coach "Land Cruiser")
1964 GM PD4106-2412 (Former Bus)
Located in beautiful Wisconsin
KD9GRB

Offline buswarrior

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Re: Leveling revisited for MCI 102
« Reply #2 on: October 12, 2019, 09:03:44 AM »
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



Frozen North, Greater Toronto Area

Offline lostagain

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Re: Leveling revisited for MCI 102
« Reply #3 on: October 12, 2019, 04:52:31 PM »
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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Offline Jim Blackwood

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Re: Leveling revisited for MCI 102
« Reply #4 on: October 12, 2019, 05:31:34 PM »
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
Information, without Knowledge, is useless.