GM Service Manual Online
For 1990-2009 cars only

Air Compressor Assembly


Object Number: 187721  Size: MF
(1)Automatic Level Control Air Dryer O-Ring
(2)Automatic Level Control Air Dryer Cover
(3)Automatic Level Control Air Compressor Cover Bolts
(4)ALC Air Compressor Head Casting Air Intake and Exhaust Opening
(5)Automatic Level Control Air Compressor Solenoid Valve Terminal Housing
(6)Automatic Level Control Air Compressor Cover Gasket

Step

Action

Value(s)

Yes

No

DEFINITION: Perform this test in order to verify the automatic level control air compressor performance and to identify and repair the potential leaks in the automatic level control air compressor assembly.

1

  1. Disconnect the electrical connection to the automatic level control air compressor assembly.
  2. Disconnect the air line from the automatic level control air dryer.
  3. Connect the automatic level control air dryer to the J 22124-B (using the adapter J 22124-98) on the side opposite of the toggle valve. Close the toggle valve (down position).
  4. Using the fused jumper wire, connect the automatic level control air compressor terminal A and E to a 12 V+ source, and terminal D and G to ground. This step will activate the automatic level control compressor motor.
  5. Allow the automatic level control air compressor to run until the J 22124-B gauge pressure reads at least 750 kPa (110 psi).
  6. Disconnect the power supply to the automatic level control air compressor.

Does the automatic level control air compressor develop at least 750 kPa (110 psi)? The automatic level control air compressor may leak down as low as 620 kPa (90 psi) after disconnecting the power. This is an acceptable level.

--

Go to Step 5

Go to Step 2

2

  1. Apply service air to the J 22124-B service valve until the gauge reads 690 kPa (100 psi).
  2. Using a soap bubble solution, check for leaks in the automatic level control air compressor assembly:
  3. • The automatic level control air dryer O-ring casting bore (1).
    • The automatic level control air dryer (2). Replace the automatic level control air dryer. Refer to Automatic Level Control Air Dryer Replacement .
    • The automatic level control air compressor head cover bolts (3).

    Tighten
    Tighten the automatic level control air compressor head cover bolts as required to 6 N·m (53 lb in).

    • The automatic level control air compressor head casting air intake and exhaust opening (4). Replace the automatic level control air compressor head if you find a leak. Refer to Automatic Level Control Air Compressor Head Replacement .
    • Around the edge of the solenoid valve terminal housing (5). Replace the automatic level control air compressor head if you find a leak. Refer to Automatic Level Control Air Compressor Head Replacement .
    • Around the edge of the cover gasket (6). If you find a leak, check the tightness of the cover bolts before you replace the gasket.
  4. Complete repairs as necessary.

Did you find and repair any leaks?

--

Go to Step 3

Go to Step 4

3

Re-apply the service air and monitor the automatic level control air compressor assembly for leaks.

Does the pressure leak down below 620 kPa (110 psi)?

--

Go to Step 4

System OK

4

  1. Replace the automatic level control air compressor. Refer to Air Compressor Replacement .
  2. Perform automatic level control system operation check to verify the repair. Refer to Automatic Level Control System Operation Check .

Was the repair completed?

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Go to Step 5

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5

Monitor the J 22124-B pressure gauge for 1 minute.

Does the pressure leak down below 620 kPa (90 psi)?

--

Go to Step 2

System OK