Rear Suspension Low Due to Failed Air Compressor on GMC Envoy

Problem Description and Possible Solution

On vehicles equipped with rear air springs, the air compressor may fail causing the rear suspension to sit low.

Problem Data
RepairPal Verified
Average mileage: 1,254,100 (11,600–190,859,680)
9 model years affected: 1998, 1999, 2002, 2003, more2004, 2005, 2006, 2007, 2008
359 people reported this problem
Viewing 1 - 20 of 189 comments
rear suspension goes down after sitting for a few hours and goes up after I start the vehicle. What has to be replaced..the air bags? how much is it going to cost
My husband is at the GMC dealer right now having our 2003 Envoy SLY rear suspension repaired. We took it in on Tuesday they did a diagnostic and tole us the compressor was burned out. Replacement $600+ and labor costs $95.00 per hour. While my husband was at home for them to call him to pick up the vehicle they then said and I quote" we put the new compressor in and parked the truck outside for a few hours and the rear fell down again." Apparently, they put it back on the lift and now say that the rear airbags have a leak and a new pair cost $465.00 plus labor. We are not letting them touch the car. We are going to bounced to the junkyards at Hunt's Point in the Bronx and buys some parts there. *I'll take my chances with my Dominican repair guy because he has never ripped me off or failed to repair my vehicle with a money back guarentee. Why didn't GM recall this truck??? This is ridiculous for this many people to be having this same expensive problem and we can get no recall? We need to get together and contact General Motors.
truck would bottom out every night but go back up when car is started the next its not leveling out now...just stays bottom out!
The rear air suspension fails to fill up when the temp drops below freezing. You can hear the compressor running, but it does not fill up. It has been looked at several times by different mechanics and no fixes seem to satisfy the problem. Only taking it inside for a few hours and allowing it to warm up seems to make it better. Which is fine for those with a garage, but not all of us have one
Rear air suspension fails in cold temperature. Took vehicle to certified dealership and recieved no answers. I am completely stumped as to why the cold would effect the air ride. It works perfect until it gets down around freezing and then will not air up on the rear. I love this car and do not want to trade so if anyone has found a solution I would be forever greatful.
rear would sag in the mornings now it wont raise at all
The air suspension fails because it's a terrible design. The primary cause of failure is the small air pressure fittings on top of the bags, it will happen on new ones too if the little hose does not seat perfectly. The seating of the hose changes when you hit large bumps. The secondary cause in the control valves in the pump, they are also poorly designed. My fix was to machine out the bags and put commercial compression fittings with commercial small diameter airlines on. Have never seen the problem again since. The fittings on top of the bags are activated with air pressure, when activated they squeeze the cheep air tube to complete a seal. This design leaks regularly right out of the fitting thus so many people have the problem. In this case the ultimate fix is not going OE, it's going aftermarket or modification.
Air bags in the rear would not air up anymore - pump is fine, replaced the air bags with coil springs
I had just bought the car and the next morning it was so low it was almost touching the ground and when I drove it it bounced alot-I called the place I bought it from and they repaired it.
The Envoy will drop when parked. Suspension gives out. The Suspension will activate again once I start up and stay good for duration of drive.
Same problem as countless others. After just a few years the rear suspension loses air overnight. Takes a few minutes to pump back up. After more time, problems worsens, as suspension is lost while driving, etc. Many, on different forums, report that entire compressor and suspension bag components must be replaced. Shops claim the same, and charge $1500 to $2000 for repairs. Common report is that compressor cannot be repaired, but must be replaced. THIS IS NOT TRUE. Now, if your loss is consistent, and unchanging, then you might have faulty rubber or connections somewhere needing attention. Do the soapy water test to look for leaks, and do what you must. BUT, if you loss is intermittent in any sense, sometimes you find it low in the morning, but other times not, then 99% of the time, you have a faulty check valve in the compressor, AND THIS CAN BE REPAIRED EASILY. It is the hardest working element of the system, most likely to develop trouble, and easy to service. YOU NEED NOT EVEN REMOVE THE COMPRESSOR FROM THE VEHICLE. There is a service plate on the bottom of the compressor, removable with 2 T-25 torques screws. Pull it, and the plate, an oval O-ring, spring, and rubber check seal, will come out. Clean the remaining metal interface of all debris and built up rubber deposits. Don't use a file or scratch anything! Clean the o-ring surfaces, and the o-ring itself, including the inside of the metal external plate removed. The rubber check valve pad will likely have a shiny circle where it meets the metal of the compressor body. This hardened rubber doesn't seal like it used to. Get some 400 grit sandpaper, with a flat hard backing, and scrub the valve pad against it until the hardened circle disappears and you have a soft virgin rubber surface again. Apply a very thin coat of silicon grease to it, and the same grease heavier to the o-ring, and reassemble. Good as new. Plan on repeating every few years. It's the hardest working component, etc. Wish I could post this on all forums, but they make it difficult to share easy, and cheap solutions. Go ahead and pay $1500 at the shop, or $0.00 for this approach. Hope this helps someone. Took much effort on my part to find out. But glad it won't bother me again.

UPDATE: So as it turned out, not quite free for me. As I mentioned, if you have a rubber problem, like old leaky airbags or hoses, that's a different animal you need to address. And I did. After a short while after repairing my compressor as described, the back end was sagging again, and especially so with heavy loads. Some soap spray revealed leaks in the air bags. After 10 years of service, they are entitled to wear out. So, bought two replacement bags, with lifetime warranties from Arnott for about $200. Very easy to install yourself. Been driving around for a couple weeks now and everything is good as new. Really, scary problem at first, but not that bad in the end.

Summary: After 10 years, it is reasonable to replace the air bladders, and $200 is reasonable. Recondition the check valve in the compressor for free, and one should get indefinite life out of that. Sound good to anyone else out there??

3 mo. Update: It's been 3 months and the very cheap and easy repair I've described is holding solid. Even with heavy load additions, I don't hear the few seconds of pumping that I'd consider normal. Save your money folks. If you're handy enough to change a tire, you can probably do this yourself. Otherwise, pass this info along to your mechanic and don't expect more than a $400 bill, total.
I have a 2006 envoy xl and the rear air compressor keeps going pumps up when car is on but if I let it set for awhile it goes down all the way to running boards are almost on the ground!!!I have replaced the fuse about 6 months ago but now having more issues....There needs to be a RECALL on this problem if all these reports have been made!!!
The rear air rides deflates to the point its almost sitting on the tires
my back end sits on the ground when the vehicle is off and it makes noises when its on that the air is filling up constantly.
Car sits low bounces around on every bump in the road. And haven't heard the compressor go off or on.can you tell what fuse number.
I replace my rear air bags with schocks
Rear air suspension fails in cold temperature. GMC Envoy XL 2004 now sits low to the ground especially in the rear. Very frustrated I just had it fixed for the same problem 7 months ago.
When car is turned off, rear suspension totally "decrease" by it self.
When car is switched back on, the aircompressor will "tilt" the air springs back up to normal.
As problem continues without repair, now suspension sometimes decrease by itself while driving and
tilt back up when stopped for more than 15 seconds.
Mechanic suggested to changed rear aircompressor for 1000 dollars.
Maybe faulty seal or air valve can be self checked and/or fixed ???
Had the fuse replaced, compressor is ok, but its doing it once again and the fuse is fine. I think there is a leak in the bags, researching coil spring conversion now! ridiculous GMC! COME ON.
Air springs failed for 2nd time. Last time dealer repaired for $800 including parts under warrant. This time, no warranty, so I bought Arnott air springs via ebay for $90/each - followed instructions that can be found several places and included with the springs. My 2005 Envoy XL Denali had compressor on driver side. Raised the back end, removed left rear tire and lowered spare to access compressor. Lowered the compressor to disconnect air lines to deflate springs. To disconnect air line on the top of the air spring, use your fingernail and push down on metal fitting on old spring and pull tube out at the same time. Turned the springs counter clockwise to remove and disconnect air line. Reinstalled new one and push line in until it seats and metal o ring on air tube rests on metal Voss fitting. I did the right rear the same but I did remove the inner fender well to access the tube easier for removal but you might not have to do that - save time and try it first w/o removing the fender well. Should be done in 2 hrs or less and it will save you hundreds if you thought of taking it to a dealer.