air suspension intermittent problem

[j-bone]

Hello one again working on my moms rainier.
The rear air bags were completely deflated I've seen it like this before but once its started it pumps back up, but for the past two days it hasn't pumped up I drove it Saturday and it was fine so sometime Monday this happened .
when car is started the compressor runs for maybe 15-20 seconds rear bags don't inflate , if you turn the pump on via the switch it runs till it times out putting out 45-50 psi so its pumping fine.
while moving it in and out of the garage trying to get it positioned just right the pump turned on and the bags started to inflate like normal ( maybe a little slower ) turned the car off shut the door and listened for a leak but couldn't hear one.
I know the switching valve in the pump is a known problem should I look at this or is it more of a sensor issue?

 

[AWD V8]

If the pump is running but the rear isn't lifting, air is leaking out faster than the pump can put it in.

The first place to look is the air bags. A common source of leaks.
Spray some soapy water on the bags while the pump is running. You should see bubbles if it's leaking.

Also the air lines can leak.

Mine were leaking when I bought my truck. I didn't want to go through the whole compressor, sensors and lines thing on an old truck. If the bags have been leaking for a while that compressor has been running overtime. I felt that I didn't want to deal with a failing compressor after replacing the bags, I just installed conversion springs and haven't looked back. Same price.

 

[j-bone]

well the system seems to be working normal now , maybe somehow the sensor got out of range or the check valve is going bad .
Ill let it be over night see if it drops and works tomorrow .
the service manual says no more then a .05" drop in 24 hours.

 

[Mooseman]

I agree. Mine was converted by the previous owner and it's been fine. After reading about so many failures of this system, I would never go back.

 

[j-bone]

Well the suspension didn't drop over night , still at ride height .
I suspect a faulty sensor

 

[j-bone]

well today after she ran some earns its back on the bump stops and wont pump back up .

 

[Tiggerr]

well today after she ran some earns its back on the bump stops and wont pump back up .

That's how mine was when my compressor puked.. no leaks but from the normal action of the suspension, it'd end up down cause the compressor wasn't working...

Swapped in a set of TB coils and called it done... Moog 81049 IIRC

 

[Instrumental]

Had similar experience. It would only put out low psi, not enough to lift the back of the truck. I replaced that check valve and that worked for a while, but I suspect working on it just knocked something into working again. Eventually complete failure.

I replaced with a stock pump I control manually, system has worked fine since.

 

[j-bone]

Can someone post up a link to the check valve rebuild kit ? I can't seem to find it .
Thanks

 

[j-bone]

After doing some more reading if the pump check valve is giving problems the pump it's self isn't too far from complete failure.
I'll do what instrumental did and clean the check valve to limp in along till the new pump comes .

 

[Instrumental]

Not sure where I found it, but I found someone who took the check valve apart and did a light sanding to remove the hardened layer of rubber on it. I did this, other then getting the pump out, pretty painless. The circle that was worn in was really obvious, and cleaned right off with a bit of fine grit sandpaper. It did work for me after that for a while, so certainly worth the time if it works.

 

[j-bone]

Well I tried to fill the bags with my air compressor via the valve in the cargo area but that didn't work . When I turned the car on the bags started to fill but slower then normal got it in the garage took some measurements and I'll see if it drops over the next few days .
I think the pump and or the valve is bad .
Also there are no fault code flashing so that would rule out a bad sensor .

 

[j-bone]

can anyone tell me how to disconnect the breather line going to pump?

 

[j-bone]

ok took the check vale apart last night its pretty bad the plate and aluminum casting are pretty well shot from moisture and cavitation.
Put it back together with some copper rtv and hoped for the best . She pumped up pretty fast this morning and now i get 80+ psi on the infiltrator hose, before i got 50 psi as best so that seems to the issue and i'm not sure how long this will hold but hopefully enough till the new one comes.

 

[j-bone]

Just one final update for everyone , the fix held for 2 weeks till i put the new arnott pump in .
the new pump blew off the safety valve on the inflater hose which the old pump never did, that's 100+psi !
pumps up to ride height much faster.
The pump as a whole was on its way out.