Replaced rear suspension airbags, now the compressor won't re-inflate.

[Emcee]

(That should say "replaced" in the title.)

I replaced the bags fine, following Arnott's instructions and some threads here. I know the compressor is still working, as it turns on when I press the inflator button inside the rear hatch. How can I trigger it to go off? Is there a trick? I've got it lifted off the ground by the rear axel right now.

Thanks!

EDIT: I should mention I did not unplug the battery, but I did remove the #1 and #15 fuses (which I have re-inserted).

 

[gmc4flash]

so I replaced the rear shocks on our 02' Envoy this afternoon... took it for a ride and thought it was riding like crap... brought it home and noticed the mud flaps scrapped on everything... put it back in the driveway and realized it was sitting all the way down on the suspension... it had never done that... could not figure it out, decided to futz with the onboard air compressor to see if maybe it had blown a fuse... when I turned it on and off several times the light on it kinda flickered and then the air bags started filling... no friggin' idea why or if it will happen again. I have a really steep driveway and I wonder if the auto level feature needs to be on level ground for it to know... (I would be shocked if this was the case). I realize this does not help you much other than... that is what I did to get mine to fill.

 

[Emcee]

Thanks for the reply. I played around with the compressor switch but couldn't get the bags to fill.

What I've got:

1. Compressor will turn on via the switch inside, it just won't fill the bags nor will it turn on automatically.
2. Neither bag will fill, at all. It is not specific to one side, so I don't think it's the ride level sensors.
3. Fuses do not look blown, but I'm going to replace both tomorrow just in case.
4. Bags are seated correctly, and the air lines are connected correctly as far as I can tell...

Of course, now I can't get the damn thing off the jack stand because it's sitting too low. Guess I'll try again tomorrow.

 

[northcreek]

Often when you change bags/shocks you lower the axle beyond normal travel. When this happens you can break the arms on the level senors over each wheel or even cause them to reverse their normal direction, picture how your knee works and imagine it reversed..Mike.

 

[Wooluf1952]

Put the jack under the hitch (add some blocks of wood if you have some). Then jack it up as far as you can. You should be able to get the truck off the jack stands and it may get the bags to inflate. With the truck jacked up you can look in and see if the sensors are broken. But, DO NOT reach in until you have stands back under the truck.

 

[Emcee]

Thank you, I'll check on the sensors. EDIT: Sensors look fine, no issues visually.

Quick question: When inserting the air line into the new bags, do you insert all the way to the little bump on the air line? If so, I may not have inserted them far enough in.

 

[Emcee]

Follow up question: If I can't get this sorted out, can I drive the car to a mechanic with zero suspension? Obviously it will be very low and I'll have to be careful, but will that cause any damage?

EDIT: Follow up question 2: I see failure of the check valve in the compressor is a common issue too. If the compressor turns on manually and air flows through the rear connector (inside the vehicle), can I rule out the check valve? Or does the check valve only factor into the suspension?

 

[Wooluf1952]

I drove mine for two days with no problems when it happened to me. Well, except for feeling like I was driving up a steep hill in a hay wagon. The rear will sit on the bump stops so nothing should rub.

 

[Emcee]

Ok. So. Egg on my face.

I finally gave up and decided to visit a mechanic I know later this week. I drove it around the block to park until then, got out, and noticed that the bags had indeed inflated to what appears to be the correct ride height.

The thing is, I never heard the compressor turn on, not like I have every time I've driven it in the few weeks I've had it. The lack of noise made me think it wasn't working.

There go 8 hours of my weekend for no reason whatsoever. Remember kids, when the manual says to give the car a full minute to see if the bags inflate, do it.

I will continue to monitor the car this week to make sure everything is all good, but I'm optimistic. Thank you all for your help!

 

[Instrumental]

I had a similar situation camping a few years ago. Our campsite had a steep approach to the pad, so when hitching up to the popup the truck was very much downhill, and then we ate lunch before we left. I pulled ahead, and ended up with the popup on the hill at a steep angle while the truck was level for a while. Pulling out of the campground felt wrong, and when I checked sure enough I was just about rubbing. Only by cycling the key a bunch of times did I get enough air to get off the ground. We took a rest stop real soon after that, and my ride height was fine by then. Scared the crap out of me on a Sunday in Canada maybe having to find service.

 

[jeffro312]

Ive driven with deflated bags for 2 weeks before 20 mins to and from work each day so nothing was damaged bumps suck you look like a fool I finally got money and just put springs in if your bags been leaking for a long time and pump gets overworked pump will go bad costly repair cheaper to do springs

 

[Emcee]

I measured the space between the fender and tire on both sides last night and this morning, and no air lost! So I think this case is closed.

 

[warriorpluto]

I know this thread is old , but one side is kind of low and the other side is regular height where it should be. The compressor kicks on everytime I start the truck. Do I need to replace the bag thats always a little low? Its not very low. Maybe just two inches lower than the other side.

 

[warriorpluto]

I want to retain the air ride suspension

 

[Mooseman]

Maybe adjusting the height sensor on the side that's low will bring it back up. I don't know if each bag can be inflated separately by the compressor or they are just split to each side from the same air supply.

Mine had bags but are now springs.

 

[Wooluf1952]

Each side is inflated separately. If adjusting the sensor doesn't level the truck, the bag may have a slow leak. Or there may be a problem in the compressor lines.

 

[warriorpluto]

How do I adjust the sensor?

 

[24v 4.2]

Does it level out when you start the truck?

 

[Mooseman]

Just behind the wheel on the frame, you should see the sensor with the arm that extends down onto the differential. It should be pretty evident how to loosen and turn the arm to adjust it.