Author Topic: Air bag tubing size  (Read 17991 times)

Offline FolkBus

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Air bag tubing size
« on: November 11, 2014, 04:21:24 PM »
Hi all,

Finally have my hardware to build my airbag leveling system.  I was wondering what you all recommend for type and size of tubing to run to each corner?  I have an MC5A

Thanks

--Mike
Mike and Debbie McNeil  Ridgway - Montrose, CO
1949 Crown SuperCoach (Amazing Grace) Conversion 1972  Pancake 220 Cummins  Fuller 5 Speed

1967 MC-5A  (Serenity)  Conversion 1986  8v-71N   Allison MT-644

Offline chessie4905

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Re: Air bag tubing size
« Reply #1 on: November 11, 2014, 05:04:40 PM »
   Mine used 1/4 inch dot. tubing. One of the original "Level It" systems.
GMC h8h 649#028 (4905)
Pennsylvania-central

Offline mung

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Re: Air bag tubing size
« Reply #2 on: November 12, 2014, 07:52:22 AM »
On that note, someone mentioned earlier that we might not really need the leveling valves on a coach because we aren't loading weight on and off.  This interests me as there would seem to be less to worry about if they were removed.  Thoughts? 
Vern in Central Florida
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Offline bevans6

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Re: Air bag tubing size
« Reply #3 on: November 12, 2014, 08:25:49 AM »
I think it's correct that our use doesn't really call for leveling valves for the reason you point out - our load is relatively stable and unchanging.  I do think that the leveling valves as stock are a simple and highly reliable system, but replacing them with control valves is likely to be equally simple and reliable.  I would stay with the tripod system of interconnecting the front so they are up and down only, and using the rears for height and side-to-side leveling.

Brian
1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
Allison MT-647
Tatamagouche, Nova Scotia

Offline solodon

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Re: Air bag tubing size
« Reply #4 on: November 12, 2014, 08:26:40 AM »
I read that also and am now going to buy the gauges, and valves so when I replace my front bags next spring, I can eliminate the factory valves (2 of which I just put on the back).  Makes sense why they're there in the first place and why we don't need them now.
Don
1979 MC9
8V71,Automatic.
Indianapolis, IN
Just getting started. Bags are in, interior metal out ready to insulate and cover, then do the floor

Offline Lee Bradley

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Re: Air bag tubing size
« Reply #5 on: November 12, 2014, 08:29:28 AM »
Possibly but I prefer having the ride height valve in place to keep the bus at the correct ride height through temperature changes, fuel level full to low, different amounts of gear on board, minor air leaks, etc. I know can manually adjust the pressure per corner or end and check the ride height but I will keep the automatic system.  

Offline OneLapper

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Re: Air bag tubing size
« Reply #6 on: November 12, 2014, 09:13:28 AM »
I used 1/4" DOT air line when I rebuilt the air bags and level valves on my 4106.

I don't think the level valves are necessarily needed, but running air lines to a remote air pressure regulator so the air pressure to the bag can be adjusted sounds like a lot of work and certainly wouldn't save any money.  But, it would be really nice to raise and lower the coach as needed, as well as help level it out when parked.
OneLapper
1964 PD4106-2853
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Offline TomC

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Re: Air bag tubing size
« Reply #7 on: November 12, 2014, 11:47:54 AM »
I kept the automatic leveling valves, but have the capability to switch to manually operated by switches and solenoids. I like the system-don't have to think about it when driving.
You should keep the 3 valve system-one in front and two for the rear to keep from twisting the bus. Good Luck, TomC
Tom & Donna Christman. 1985 Kenworth 40ft Super C with garage. '77 AMGeneral 10240B; 8V-71TATAIC V730.

Offline mung

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Re: Air bag tubing size
« Reply #8 on: November 12, 2014, 12:03:36 PM »
That is my plan as well. I have 3 solenoids that I am going to be putting inline with the bag lines so that I can bleed air off of when parked if I want to.
Vern in Central Florida
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Offline Tony LEE

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Re: Air bag tubing size
« Reply #9 on: November 12, 2014, 02:52:10 PM »
Quote
why we don't need them now.

I think you do. Go from full to empty fuel and or full to empty water and or full to empty waste tanks and there can easily be a ton or more of weight moving from front to back and side to side and that isn't trivial.

Where does this fear of failure of height valves come from. Probably one of the most reliable systems on the whole vehicle, possibly because to a certain extent it is leak tolerant. Get rid of it and I'd say you will be driving with a list more often than you would like.

Given that most "normal" large motorhomes do have levelling valves, wouldn't you think there might be a good reason.

Offline Dave5Cs

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Re: Air bag tubing size
« Reply #10 on: November 12, 2014, 03:13:10 PM »
I used 1/4" DOT Vinyl lines to each corner and a supply from the supply tank to the air control valve. 4 Paddle switches and 2 gauges with 2 needle arms on each gauge. So I can adjust and have any corner or all at once which ever i choose too. Has effected anything other than leveling at campsites without having to use my blocks and if going down the road and my levels show out and i can feel it I just reach next to my seat and push a valve to adjust. Most of the time I set them before I leave and never have to adjust them unless we stop at a campsite for the night and it is not level. I left the leveling valves in but disconnect them long ago.

Dave5Cs
"Perfect Frequency"1979 MCI MC5Cs 6V-71,644MT Allison.
2001 Jeep Cherokee Sport 60th Anniversary edition.
1998 Jeep TJ ,(Gone)
 Somewhere in the USA fulltiming.

Online luvrbus

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Re: Air bag tubing size
« Reply #11 on: November 13, 2014, 05:52:07 AM »
www.hwh.com so many different ways to do a air leveling system you can find the schematics for about all on their site
Life is short drink the good wine first

Offline Oonrahnjay

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Re: Air bag tubing size
« Reply #12 on: November 13, 2014, 06:44:27 AM »
   www.hwh.com so many different ways to do a air leveling system you can find the schematics for about all on their site 

   Thanks, Clifford.  That website is very useful.
Bruce H; Wallace (near Wilmington) NC
1976 Daimler (British) Double-Decker Bus; 34' long

(New Email -- brucebearnc@ (theGoogle gmail place) .com)

Offline gus

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Re: Air bag tubing size
« Reply #13 on: November 13, 2014, 02:08:55 PM »
On that note, someone mentioned earlier that we might not really need the leveling valves on a coach because we aren't loading weight on and off.  This interests me as there would seem to be less to worry about if they were removed.  Thoughts?  

It is true they don't serve a useful purpose in a conversion as they are originally designed for passengers and cargo, but they do offer a real opportunity to serve as the basis for a manual leveling system for parking.

If removed you would still need some system for keeping the bags inflated. They do/will leak!!
PD4107-152
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Offline CoachServices LHC

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Re: Air bag tubing size
« Reply #14 on: November 13, 2014, 03:10:30 PM »
people thinking they are going to twist bus with 4 valves need to draw a sketch  and think hard. if you still think 3 is better probably shouldn't own a bus or give other people advice
1964 4106 871T 730 with 4 corner leveling

 

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