Rear Suspension bags - Page 2

wildtoad · 03-06-2004, 02:57 PM

So today I go out with my handy dandy spray bottle of windex to check for leaks at the tank, pump, etc. I turn on the key, the pump starts and pressure starts to build. I spray the fittings at the tank, pump, bags and no air appears to be leaking. I turn the petcock valve and low and behold air does come out this time, so this is the accum. tank. The pump pumps until it reaches 130 psi and shuts off and it appears to hold so I surmise there is no leak, or at least no significant one.

So now I go to the left side rear tire which is near the area where the leveling device is mounted and start rocking the boat side to side. With each "rock" I hear air escaping from under the RV indicating the leveling device is doing what it supposed to do. After several times, I hear the pump start up again to replenish the accum. tank. So I think things are working as designed but perhaps the tank/pump is too small for this type of application.

Jim, you say it should pump range should be between 70 and 105 psi. Is there an adjustment for this on the pump or is it preset at the factory ?

Does anyone know if there is an adjustment as to how much air is released from the bags or a way to adjust when the air is released so that only significant rocking causes the gates to open?

thenewkid64 · 03-06-2004, 03:32 PM

Max Psi is based on the coach. On the older classics it was a lower max. There should be a gray box Teed into the line right at the compressor this box has the pressure switch in it. If Yo want to adjust the cut off pressure you remove the cover and there is an adjuster in there. I do not know of a way to set the leveling valves to not purge air in a rocking situation. One thing to check is the condition of your shocks. The rig could just me moving too far and causing the valves to activate.

Based on your symptoms I would be willing to be there is a check valve in the pump and it is failing. This valve allows the pressure to leak out of the system and the pump has to restart to re-pressurize the system. A check valve can be added between the pump and the T fitting to stop this. The additional check valve will also prolong the pump life because the pump will be starting with little or no back pressure at startup.

wildtoad · 03-06-2004, 04:01 PM

I think the shock idea has some merit. Thanks.

jim8860 · 03-06-2004, 04:52 PM

jim8860 · 03-06-2004, 04:53 PM

jim8860 · 03-06-2004, 04:57 PM

Here is a pic on my MH after a week of parking

jim8860 · 03-06-2004, 05:03 PM

Here is my new tank . My tanks only leaks when I am driving and under heavy loads.

jim8860 · 03-06-2004, 05:05 PM

The air bags do not have check valves. the ride height controler un the MH does all that.Look for crack on your tank .Place your and and try to feal air leaking. here is a pic where my tank is cracked.

jim8860 · 03-06-2004, 05:10 PM

One more . The line down the frame can have a leak in it.You can buy the stuff at any "BIG" rig store (tractor trailers). It called synflex ( check the spelling on it) the stuff is cheap, plus you will a few new fitting as well. The photo posted is where the air gauge comes in . The shocks will help the bounce and ride quality but not a the compresser from turning on or off. Good Luck

wildtoad · 03-06-2004, 05:17 PM

Jim,

Thanks for all the great posts and pictures. I did not find any leaks or cracks in the tank. Now, I have the same pressure switch. I took off the cover and there are instructions to adjust the cutin and cutout pressure. The factory setting were and are 100/130.

Thanks

jim8860 · 03-06-2004, 05:52 PM

No clue!!! Sorry but I am sure they must be a high side and low side cut off points.Its dark by me now, I will take look on my on Sunday. If you play with them, they will only need a 1/4 to 1/2 turn to make a change.

wildtoad · 03-06-2004, 06:10 PM

Seems you replied before I could edit my post. I found the instructions and actually read them... Boy I hate that... I may do some more fine tuning but it got dark. It nows cuts out around 105 and in around 75. Thanks again. I still need to take it for a test drive to see if any of this has affected anything.

jim8860 · 03-06-2004, 06:25 PM

You should be in good shape now. Enjoy, I still have to install my new tank and clean up the mess that the "other" people left for me. Jim

zamboni · 03-06-2004, 09:35 PM

Our 79 service manual covers the entire air ride system...it also covers adjusting the "ride height" and ride feel of the rig. Have you checked those? I remember a thread about this about a year ago.
I don't know if the newer manuals are as detailed as the older ones. Sounds like the systems really haven't changed much in 25 years. If you need a copy of the couple pages for referrence, PM me and I'd be happy to email to you.