AutoRide Compressor pooped

MichEnvoyBoy · February 20, 2006

My 02 Envoy SLT's autoride compressor finally gave out at 82k miles. I brought it into the GMC dealer, who wants $500 for the pump and $250 for labor. I figured since the compressor is right back by the passenger fender/cargo area, that it wouldnt be "that hard" to replace.

Question: How do I remove the old compressor? Through the rear wheel well or the cargo area?? When I install the new compressor, do I just install it and Im good to go??

the dealer already tested the autoride system because my compressor just completely quit after being really noisy for a while. They bled ALL of the air out and now my truck rides like 4" from the ground...LOL Any suggestions on the compressor?

gmpartsguy · February 27, 2006

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Air Spring Compressor Replacement

Removal Procedure

Caution: A sudden release of pressure may cause personal injury or damage to the vehicle. The air suspension system is under pressure until the air supply lines are disconnected. Use the following precautions when servicing the air suspension system:

• Wear gloves, ear protection, and eye protection.

• Wrap a clean cloth around the air supply lines.

Notice: Depressurize the air suspension system only after the rear axle is supported and is set between D- Height and Full Jounce.

Important: Remove the air suspension system fuse before working on the rear suspension components or the rear axle. Failure to remove the air suspension system fuse could cause the calibration of the air suspension leveling sensor to change and the air suspension system not to function properly.

Remove the air suspension system fuse.

Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

Remove the air spring compressor to the frame mounting bolts.

Disconnect the air inflator switch electrical connection, air supply lines, and air spring compressor vent hose from the air spring compressor.

Disconnect the air spring compressor electrical connection (2).

Important: Ensure the color on air supply lines match the color on the air spring compressor for reassembly.

Disconnect the air supply lines (3) from the air spring compressor (1).

Remove the air spring compressor from the vehicle.

Installation Procedure

Notice: Refer to Fastener Notice in Cautions and Notices.

Important: Inspect the air supply lines for deep scores or cuts. If the air supply lines are damaged the lines must be replaced.

If no damage to the air supply pipes is evident, then remove the fittings from the new compressor and use existing fittings that are already attached to air supply lines. Install the air supply lines with existing fittings to the air spring compressor.

Tighten

Tighten the air supply line fittings to 2.25 N·m (20 lb in).

If damage is evident to the air supply lines, then replace the air supply lines. Refer to Air Suspension Air Line Replacement .

Connect the air spring compressor electrical connection (2).

Connect the air inflator switch electrical connection, air supply line, and air spring compressor vent hose to the air spring compressor.

Install the air spring compressor to the frame mounting bolts.

Tighten

Tighten the air spring compressor to the frame mounting bolts to 20 N·m (15 lb ft).

Lower the vehicle.

Install the air suspension system fuse.

Start the vehicle and run for approximately 1 minute to ensure that the air spring leveling system is functioning properly.

Inspect D height. Refer to Trim Height Inspection Procedure in Suspension General Diagnosis.

Inspect for leaks. If a leak is found at the air supply lines connections at the air spring compressor, replace the air supply lines. Refer to Air Suspension Air Line Replacement .

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Document ID# 748990

2002 GMC Truck Envoy - 4WD

Hope this helps

gmpartsguy · February 27, 2006

2002 GMC Truck Envoy - 4WD

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Trim Height Inspection

Trim Height Measurements

Trim height is a predetermined measurement relating to vehicle ride height. Incorrect trim heights can cause bottoming out over bumps, damage to suspension components, and symptoms similar to wheel alignment problems. Inspect the trim heights when diagnosing suspension concerns and before inspecting the wheel alignment.

Perform the following prior to measuring trim heights:

• Make sure the vehicle is on a level surface, such as an alignment rack.

• Set the tire pressures to specifications. Refer to Label - Vehicle Certification in General Information.

• Check the fuel level. Add additional weight if necessary to simulate a full tank.

• To ensure proper weight distribution make sure the rear storage compartment is empty.

• Close the doors and hood.

Z Height Measurement

The Z height measurement determines the proper ride height for the front end of the vehicle. Vehicles equipped with torsion bars use an adjusting arm to adjust the Z height. Vehicles without torsion bars have no adjustment and may require replacement of suspension components.

Important: All dimensions are measured vertical to the ground. Cross vehicle Z heights should be within 24 mm (0.9 in).

Place hands on the front bumper and jounce the front of the vehicle. Make sure that there is at least 38 mm (1.5 in) of movement while jouncing.

Allow the vehicle to settle into position.

Measure from the centerline (1) of the lower control arm bushing bolt (4) down to the machined edge of the steering knuckle (2) in order to obtain Z height measurement (3).

Repeat the jouncing operation and measurement 2 more times for a total of 3 times.

Use the highest and lowest measurements to calculate the average height.

The true Z height dimension number is the average of the high and the low measurements. Refer to Trim Height Specifications .

If these measurements are out of specifications, inspect for the following conditions:

• Sagging front suspension. Refer to Shock Module Replacement in Front Suspension.

• Collision damage.

D Height Measurement

The D height measurement determines the proper ride height for the rear end of the vehicle. There is no adjustment procedure. Repair may require replacement of suspension components.

Important: All dimensions are measured vertical to the ground. Cross vehicle D heights should be within 12 mm (0.5 in) for vehicles equipped with coil springs, vehicles equipped with air suspension should be within 8 mm (0.3 in).

Place hands on the rear bumper and jounce the rear of the vehicle. Make sure that there is at least 38 mm (1.5 in) of movement while jouncing.

Allow the vehicle to settle into position.

Measure the D height by measuring vertical distance (2) between the jounce bumper reinforcement bracket (4) on the frame (1) and the top surface of the axle tube (3).

Repeat the jouncing operation and measurement 2 more times for a total of 3 times.

Use the highest and lowest measurements to calculate the average height.

The true D height dimension is the average of the highest and lowest measurements. Refer to Trim Height Specifications .

If these measurements are out of specifications, inspect for the following conditions:

• Sagging rear suspension. Refer to Coil Spring Replacement in Rear Suspension or Symptoms - Air Suspension in Air Suspension.

• Collision damage.

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Document ID# 742595

2002 GMC Truck Envoy - 4WD

MichEnvoyBoy · March 1, 2006

I ended up replacing the compressor last week and I can tell you that I did not check any distances "Z height, D height" whatever the heck that was. I basically put a jack under my hitch and held it up as I released the pressure. Then I replaced the compressor and put the new one on, put the fuse back in and started it up.

Pumped up "just like new". The new compressor is so quiet I can barely hear it! Much different than the old one that has been clattering for months.....