1995 Chevrolet P30 Air Bag Pressure

[bjarnold]

I had the air bags replaced on my 28ft Bounder and in the GM manual it shows the recommended pressure 60-100psi but Air Lift recommends 40-90. Should I go by the air bag manufacturers pressure or chassis manufactures pressure?

[turbojimmy]

happycamper002 wrote:
Big nonsense, CW replaced the blown airbag and corrected the problem.
How do you explain that.I still have the blown air bag to prove my point.

Try to make more sense in what you say to make yourself believable.

An Rv tech doesn't make an engineer.

I'm sorry but you're confused. Chevy put air bags inside the FRONT coils on the P-30 chassis to compensate for the load that the motorhome places on the front axle. When they manufactured the chassis they didn't know whether it was ultimately going to be a motorhome, bread truck or whatever. They are a band-aid of sorts - the right thing to do is to size the coil springs to the load on the front axle. Both my front bags are blown and the rig sits just fine. Handling is a bit sketchy - bags are on the to-do list. I've been driving it for years with no bags despite dire warnings in the manual that the front tires will shred pretty much immediately (didn't happen).

Rear bags, as mentioned, did not come from the factory. The factory setup on the P-30 was rear leaf springs. Nowhere to put bags even if you wanted to (EDIT: there are air bag helper spring kits, but not for the big truck chassis that I'm aware of). Some manufacturers and owners opted for aftermarket airbag systems that completely replaced the stock leaf springs. In this case, the airbag is taking the place of the spring rather than just providing a bit of help it as with the bags in the front coils. If a rig equipped with a rear air bag system blows, it will drop to the ground. I'm surprised you were able to drive yours. I have a slow leak in my right rear bag (Jet Ride air suspension) and when it leaks out completely (takes a few months in storage) it's sitting right down on the ground.

So this blown bag you have - is it a big black thing or a skinny red thing?

[happycamper002]

Big nonsense, CW replaced the blown airbag and corrected the problem.
How do you explain that.I still have the blown air bag to prove my point.

Try to make more sense in what you say to make yourself believable.

An Rv tech doesn't make an engineer.

[dougrainer]

happycamper002 wrote:

darsben1 wrote:

This is the correct answer.

This is misinformation that shouldn't have been. You obviously haven't experienced a blown air bag on one side. I have the same size MH that OP has and I blew the passenger-side rear bag while driving from a lakeside CG in CA.

I couldn't stop on a single lane steep mountain road to check, and besides, there wasn't much I could have done anyway so I kept driving until I got to the nearest town. I pulled into a gas station and the best advice I got from the mechanic was I needed new shocks. (duh)

All that time I was driving from the mountain road, I got some well-meaning motorists behind me motioning that I'm leaning over to tip the MH due to bad off-level condition.

I have also witnessed school buses with blown air bags with the chassis almost touching the pavement.

I deflated the opposite side air bag to almost even out the off-level side to make it home that was almost 100 miles away.

My motor home and I assume most of them are, has almost all the weight on the passenger side: water heater, range, fridge, kitchen cupboard, 32 in flat TV, hood, propane tank and even the motorized doorstep. And to make things worse, the road crown is always sloping to the passenger side making liquid in tanks like fuel, waste and fresh water to settle or nest to that side too.

Weighing an empty RV doesn't reflect the real world condition.

I always check the level and pressure to achieve the level that I'm comfortable with. It doesn't have to be perfect but at least motorists behind you would not be concerned about you falling over the cliff when driving the shoreline of the Pacific Ocean in Northern CA.

Yes, to a certain extent, it does help in keeping the MH level.

You state you had a problem with REAR airbags. YOU obviously do not know what you are talking about. There is a difference between the P-32 and the OLDER P-30 Chevy chassis. As I stated, on the P-30 chassis, the inside the FRONT coils, CHEVY installed the Air bags to INCREASE the front load capacity of the Front end. Chevy never installed REAR air bags on a P-30 chassis, but some OEM Class A makers did. The CHEVY P-30 chassis REQUIRES operational air bags for correct front end handling. You can use aftermarket air bags which a lot of people do. I worked on Chevy Class A motorhomes from 1979 until about 1991, when we dropped chassis service. I STILL am a RV Technician and have been for 37 years. Doug

AND, your statement about Load distribution. Poppycock. It all depends on the floorplan and the OEM maker on how appliances and various items are installed on the RV. They do NOT load up the pass side or even one side as a standard design. They DO try to equalize the load distribution to some extent.

[ets1996]

My understanding of the airbags on my p32 chassis is to adjust ride height. I have some instruction some where which states aside from weight axle/corners of the motorhome should be unloaded storage, tanks etc. then on flat parking Measure bumper height front and rear Then with coach loaded for travel use the airbags to return to empty ride height with out exceeding max air pressure rating.

[happycamper002]

darsben1 wrote:

This is the correct answer.

This is misinformation that shouldn't have been. You obviously haven't experienced a blown air bag on one side. I have the same size MH that OP has and I blew the passenger-side rear bag while driving from a lakeside CG in CA.

I couldn't stop on a single lane steep mountain road to check, and besides, there wasn't much I could have done anyway so I kept driving until I got to the nearest town. I pulled into a gas station and the best advice I got from the mechanic was I needed new shocks. (duh)

All that time I was driving from the mountain road, I got some well-meaning motorists behind me motioning that I'm leaning over to tip the MH due to bad off-level condition.

I have also witnessed school buses with blown air bags with the chassis almost touching the pavement.

I deflated the opposite side air bag to almost even out the off-level side to make it home that was almost 100 miles away.

My motor home and I assume most of them are, has almost all the weight on the passenger side: water heater, range, fridge, kitchen cupboard, 32 in flat TV, hood, propane tank and even the motorized doorstep. And to make things worse, the road crown is always sloping to the passenger side making liquid in tanks like fuel, waste and fresh water to settle or nest to that side too.

Weighing an empty RV doesn't reflect the real world condition.

I always check the level and pressure to achieve the level that I'm comfortable with. It doesn't have to be perfect but at least motorists behind you would not be concerned about you falling over the cliff when driving the shoreline of the Pacific Ocean in Northern CA.

Yes, to a certain extent, it does help in keeping the MH level.

[enblethen]

I replaced my front springs with variable coils with no air bags from Henderson lineup.

[bjarnold]

Right now I have them at 80psi. After the old bags were replaced the front end did come up noticeably. Before it looked like a hod rod with the nose to the ground. Now it is sitting just about level. I put a level inside the freezer and it's actually sitting a little nose high

[darsben1]

dougrainer wrote:
P30 air bags in the FRONT coil springs are NOT to level the motorhome. They are required and designed to INCREASE the front suspension load carrying capacity. Nothing else. AND you use the Chevy recommended pressures. Doug

This is the correct answer.

[harold1946]

DougE wrote:
I think one thing the air pressure pundits overlook is a primary function of the airbags to level the RV. Chevy had no idea how much load the RV manufacturers would be putting on the front end so the airbags give the ability to level the unit. So find a level slab, put a level on the RV floor and adjust the airbags accordingly. You may even find that getting the top of the wheel well even on both sides may require different pressures in each side.

On the P32 chassis the air bags have nothing to do with leveling the unit. They are for assisting the springs and adjusting for suspension loading, (the amount of weight being carried) and maintaining the ride
height.
Both bags should have the same pressure at all times.

[dougrainer]

P30 air bags in the FRONT coil springs are NOT to level the motorhome. They are required and designed to INCREASE the front suspension load carrying capacity. Nothing else. AND you use the Chevy recommended pressures. Doug

[enblethen]

Check vin number for what the front end is rated.
Weigh the rig.
Adjust air according to percentage based on Air Lift manual.
70 pounds would be about min. I would guess closer to 80-85 PSI.

[DougE]

I think one thing the air pressure pundits overlook is a primary function of the airbags to level the RV. Chevy had no idea how much load the RV manufacturers would be putting on the front end so the airbags give the ability to level the unit. So find a level slab, put a level on the RV floor and adjust the airbags accordingly. You may even find that getting the top of the wheel well even on both sides may require different pressures in each side.

[crasster]

harold1946 wrote:
I suggest 70 psi. as a good starting point. Then adjust from there, up or down until you find the sweet spot, where the ride and handling suit you best.
I do not recommend going below 50psi.

X2. When all else fails and mfgs say something different than other mfgs go somewhere in the middle.

[harold1946]

I suggest 70 psi. as a good starting point. Then adjust from there, up or down until you find the sweet spot, where the ride and handling suit you best.
I do not recommend going below 50psi.