GM Leveling Valve Question

[eagle19952]

What did you use for manual leveling valves?

many use air seat height adjust valves

[sledhead]

how I did mine
1 air line from each corner to the drivers seat area to a control unit
4 in from air bags and 1 out to fill the bags . so 5 air gauges
push to add air pull to let air out .
no power needed no switch no wire just air . as Tom I could adjust height at any time from the driver's seat

I wish the featherlite had this kind of system way way simpler then the H and H system

dave   

[richard5933]

how I did mine
1 air line from each corner to the drivers seat area to a control unit
4 in from air bags and 1 out to fill the bags . so 5 air gauges
push to add air pull to let air out .
no power needed no switch no wire just air . as Tom I could adjust height at any time from the driver's seat

I wish the featherlite had this kind of system way way simpler then the H and H system

dave

Interesting.

The GM uses one leveling valve in front and two in the rear. Does that mean I'd use three controls in my setup? Something about not wanting to twist the body by using four-corner lifting on the GM.

If I understand this correctly, all three of the current valves would be eliminated. The air to fill the air bags originates in the aux tank. I'd re-route that feed from the aux tank to this new control panel, and then three lines would be run - one to the front and one to each side in the rear, and these new lines would be what fills the air bags as controlled by the driver.

Where does the exhaust port run on your setup?

[sledhead]

the exhaust is right at the valves . no stink just a slight rubber smell at times
I liked the 4 corner system as when on uneven ground it worked great .
it was easy to install other then the 1 piece air lines from each corner to the unit ( no connections  ) I installed a 10 gal. air tank with a one way valve from the auxiliary air tank . the system would hold air for months

dave

[chessie4905]

The one I have has a line from front tank under driver to selector valve and line going back to origonal line that goes to leveling valve supply. The selector valve either gives highway position and operates leveling valves in normal operation or in parking or camping position, it routes air to individual air bags through 4 push-pull valves with 4 attached  pressure gauges. Between each line going to each air bag there is a Bendix double check valve. The center port connects to air bag. Of the two remaining ports, one connects to output of leveling valve. The other port connects to one of the push-pull valves. There is a shuttle piston in the double check valve. If air is supplied from leveling valve, the air pushes piston and it blocks port from push-pull air supply. If air is supplied from push-pull valve, piston moves to block air supply from leveling valve. Two double check valves are used at front bags and lines are separated from left and right bags. They all four work together normally in highway position, and the left and right pairs work individually in parked or camping position.
As far as twisting body, if you are on unlevel ground, you aren't twisting body, you are making it plumb and level. The axles are doing the twisting, although twisting isn't the correct term in this case. To twist body, you need a plumb and level coach and then add significant pressure to one or opposing airbags. Why would someone do that? Due to the way our coach bodies are constructed, I think it would be hard to get any significant twist.

[dtcerrato]

For under $50 dollars & two days work (with a pit) we put 12 vdc solenoids at all three valves enabling us to manual level when camping or parking. We carry blocks if its extreme but only use them a fraction of the time. Four toggle switches in the drivers cockpit for the three solenoids at the levelers & one at the aux. air tank to exhaust down to 65 psi so the levelers wont try and re-level. Other than that the entire air suspension system is as designed. We like it.

[TomC]

You can exhaust the air down each time as explained above, or install an additional 12v normally open solenoid between the auto leveling valve and the air bag. This cuts off the auto leveling valve. Then between the normally open solenoid and the air bags install a T to have the other two normally closed solenoids-one for adding and one for exhausting. I have that system (3) and works well. Takes all of about a minute to level the bus at campsite. Good Luck, TomC

[richard5933]

UPDATE:

Picked up the bus today from Interstate. They've got a senior tech there with decades of experience on GM and MCI buses. He worked a day and a half on my bus. I didn't think it would take that long, after all it was just changing shocks and leveling things out. However, he knows how OCD I am about these things, and he got it right.

First, the shocks made a HUGE difference. I had no idea how worn out the old one were, but apparently they were really worn out. The bus handle dips, bumps, and curves in the road with much more stability and nearly no bouncing now. And these were just original equipment style shocks from Luke, and they were only $66/ea. Very impressed with the improvement a set of shocks can make.

The leveling issue was apparently a combination of the failed shocks and a very finicky set of valves. The extra up & down motion from the failed shocks was not allowing the leveling valves adequate time to do their job as they were constantly trying to adjust. Once the new shocks were in the tech was able to get things set correctly.

Very happy bus nut today.

[pd4501-771]

Glad you resolved your issue. Congrats.

[dtcerrato]

Glad to hear your shocks remedied at least a couple woes. We're really looking forward to seeing the ride difference in our bus since we're putting new shocks on.especially after reading how impressed you were with the shocks change out & your ride

[gg04]

Adjustable gas shocks were not an option with Gabriel nor Monroe when cross referencing from replacement part numbers from da book.
[/t
quote]
Bought ours from a truck parts store based on open-collapsed length, and load..were Monroe's .