Mechanics

REAR AIR SUSPENSION

2003 GMC Envoy

Suspension problem
2003 GMC Envoy V6 Four Wheel Drive Automatic 75000 miles

My 03 Envoy air compressor will not inflate the air suspension. The accessory outlet for the compressor is producing about 31psi. The rear end is sitting way down with a little bit of air in the shocks but will bottom out easily. I don't think it is a leak as this is the second time this has happened. The compressor comes on for about 30 sec to 1 min at startup but no increase in ride hight. The last time it happened I parked with one wheel on the curb, re-started the engine and when the compressor kicked in I raised and lowered the back end by lifting on the trailer hitch. This inflated the airbags for about 2 months. The most recent drop in the suspension coincided with a dead (bad) battery. The battery has been replaced. Is there an overload reset? As the symptoms mimic what the manual says the suspension will do in the event of an overload.
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Brokeback envoy
December 7, 2007.




Hi, my 2003 Envoy has the exact same problem. Dealer informs me, the pump is shot. Did you find a solution for yours? Very curious what the root case was.

Tiny
Stark
Feb 10, 2008.
I just repaired one. The compressor has two parts: An electric circuit board with solenoids that route pressure to whichever side is low. Nothing goes wrong with any of the electronics or electric motor. And it has a trunk air compressor. Both are powered by a single teflon ringed piston spun by an electric motor. The part that goes bad is what's actually the connecting rod bearing. In this case it's a needle bearing. It disintergrates and particles of steel get trapped between the


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Teflon rings in the aluminum cylinder. The whole assembly also goes off center with all the sloppy movement that interrupts the way the piston inhales. Mechanically, it keeps working because the motor still spins the piston, although very sloppy and destructive until the plastic rod shatters. So don't keep turning it on from the trunk, you may be able to save it. I actually repaired mine by buying a pack of two 9/16 plastic hole plugs at Lowe's for .99 cents. I drilled a 9/16 hole through where the spun bearing was and plugged it with the two plugs, one on each side. Then melted in a 6mm deep socket from one end, leaving the other end closed. (The 6mm deep socket with 1/4 in. drive is exactly 12mm) Pushed in two new needle bearings (6mm Inner Diam. and 12mm Outer Diam.) Loaded it with some grease and reassembled. *Some advice: Don't use the compressor from the trunk. This is a very expensive setup for the air suspension, so if you need air, go to the gas station or use another compressor at home.
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Tiny
Wilsemail
Apr 11, 2008.
I am trying to do the repair listed above but I don't understand the steps.

Did you completely disassemble the compressor? How did you get the electric motor disconnected from the pump body?

Tiny
Envoy03
Dec 31, 2008.
You also may want to check the sync of the inflation system, watched a guy at work sell the compressor and shocks to someone and it was just out of calibration.

Tiny
SamG
Dec 13, 2010.

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