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2002 gmc envoy_slt
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111 Posts
Discussion Starter · #1 ·
I have an '02 Envoy SLT with the air suspension. It seems the compressor was getting louder and running more frequently as I've had this thing, but I did notice it was raising the truck every time it went on.

The other day I was driving and I heard a boom from the back, then a clatter like something was caught in the wheel. I pulled over twice, but couldn't find anything out of place. The clatter went away, but now:

1. The compressor goes on when I start the truck, and I never hear it again;
2. The rear end is lower than the front, but not on the ground;
3. When the compressor goes on at startup, the truck does not raise up.

Ride height at the top of the wheel well is 32.5 in the front and 30.5 in the rear.

What happened, and how do I fix it?

Thanks!
 

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2004 gmc
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26,436 Posts
You lost a hose, or the compressor is kablooie. It tries for a while, sees the ride height doesn't change, and its computer shuts it down so it doesn't run forever and drain your battery.

Expensive to replace unless you find one on Ebay, where they show up intermittently. If the air ride doesn't mean much to you, there is a kit you can buy to replace the air bags with springs, or just buy some takeoff springs from somebody who's done a lowering kit. Check the classifieds or Ebay. Run a search here on "replacing air ride compressor"
 

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2004 gmc
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They're all interchangeable. Long wheelbase belongs with long wheelbase, but it looks like both of you are SWB. There are many spring rates according to the options in the vehicle, but that was GM engineers striving for excessive ride consistency, not for any reasonable purpose.

The aftermarket strutmasters.com kit includes shocks and springs, for about $400, but they only offer one kind of spring, as if they never knew what the GM design team was up to. I wouldn't be surprised, since it took us years to discover it on trailvoy.
 

· Premium Member
2003 gmc envoy_slt_xl
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117 Posts
Sounds like you lost the air compressor head, which is what happened to me. You won't know until you do a visual on the compressor which is frame mounted at the rear of your voy. XL's are mounted in a different location. See if a hose popped, or more likely that the compressor is missing it's compressor head probably do to the air piston failure. If that's all it is, there's a plug 'n play solution. Not cheap, but a whole lot better that the dealer will charge. See link below.

http://www.arnottindustries.com/part_GMC_Air_Suspension_Parts_yid15_pid120_gid488.html
 

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2003 gmc envoy_slt_xl
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82 Posts
While this discussion is fresh I'll ask this...

I've been convinced I need to take my system out and replace with coils. This is based on my Envoy's intermittent problem as well as the consensus that the system is way overpriced parts wise for the quality.

Mine sags on the right side under certain conditions. If I park on an incline the next morning the right is at 29", left at 31. I start the vehicle and the compressor kicks on raising the right to 33.5 and left to 34. It will stay that way most of the day especially if driven or parked level.

I 'm wondering if I might have a leak and if so what's the best way to check? Hopefully this is a simple, even if temporary fix as I'm going on a road trip and the coils I plan on installing require 3-5 business days shipping. That's if I have the correct part numbers!
 

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2004 gmc
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The hoses could leak, the air bags themselves can have age cracks and leak, and the compressor valves for each side could leak. Hard to diagnose without some time and gauges. You could always spray it all down with soapy water and look for bubbles.

The side to side height issues when it's pumped up are the sensors, which are behind each rear wheel and easy to adjust rotationally. Just do them a tiny bit at a time if that 1/2" annoys you.
 

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2002 gmc envoy_slt
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111 Posts
Discussion Starter · #8 ·
Ok I ordered the compressor from Arnotts, install looked too easy to pass up, and I'm leaning towards it being the compressor because the inflator isn't working either even though the light is on. I'm a bit intimidated by swapping it out for springs, so I'll go the OEM replacement route till the bags blow up...I'll post again when the install is complete. Thanks!
 

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2002 gmc envoy_slt
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111 Posts
Discussion Starter · #9 ·
I've been thinking about this install, and i have a couple questions. The Arnott's manual is basically 1 page, unbolt, unplug, reverse, and voila... What else do I need to do here? I mean won't there be pressure in the lines/bags? and I'm assuming disconnect the battery? I just don't want to give myself and headaches. :bonk: Any advice would be helpful....
 

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2003 gmc envoy_slt
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8,149 Posts
You should get at least a Haynes manual. Remove the fuse for the compressor. Support the axle and remove the pass. side tire. Support the body and the axle at ride height. Wear safety glasses when you disconnect the air lines. The air supply lines should be tightened to 20 INCH lbs. (That's not much) Compressor mounting bolts to 18 ft.lbs. There are also places to measure to get the correct height and procedures to use.
 

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2002 gmc envoy_slt
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111 Posts
Discussion Starter · #11 ·
Repaired!

Well once again I give thanks to my friends at TrailVoy:hail::hail:. I ordered the compressor from Arnott's, had it shipped overnight, and it arrived today. Removed the "COILS" and "RIDE" fuses, both sounded right, so I took no chances. Unbolted the old one, had to saw 2 of the bolts connecting the old compressor to the plate because of rust. The new compressor came with new rubber bushings and new bolts, so no issues there. Connected everything back up, I used the same hose fittings even though the new compressor came with new fittings. Replaced the fuses, turned the key, and after a few tense moments:ugh:, I am back in business! :woohoo: The bags lifted right up, the Envoy is level again! :woot: Thanks again everyone! :thx
 
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