GM Service Manual Online
For 1990-2009 cars only

Park Brake System Diagnosis Disc

Step

Action

Yes

No

DEFINITION: This diagnostic table is designed to diagnose ONLY the components of the PARK brake system in order to determine if the PARK brake system is operating properly. You will be directed by the appropriate Symptom table to go to other brake system diagnostic tables as appropriate.

1

Were you sent here from a Hydraulic Brake Symptom table?

Go to Step 4

Go to Step 2

2

Were you sent here from a Park Brake Symptom table?

Go to Step 4

Go to Step 3

3

Is the symptom related to the ability of the park brake system to hold and/or release?

Go to Diagnostic Starting Point - Park Brake

Go to Diagnostic Starting Point - Hydraulic Brakes

4

  1. Raise and support the vehicle with the rear axle supported by jack stands. Refer to Lifting and Jacking the Vehicle.
  2. With the park brake RELEASED, attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.

Do the rear brakes have a significant amount of drag?

Go to Step 9

Go to Step 5

5

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.

Do the rear brakes have a significant amount of drag?

Go to Step 6

Go to Step 7

6

  1. Release the park brake.
  2. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag.

Did the rear brakes exhibit a significant reduction in the amount of drag?

Go to Step 18

Go to Step 12

7

Visually inspect the park brake cable connections and the cables that are accessible on the UNDERSIDE of the vehicle for disconnections and/or damage.

Were any of the park brake cables disconnected and/or damaged?

Go to Step 8

Go to Step 9

8

Reconnect or replace the park brake cables as necessary. Refer to Parking Brake Rear Cable Replacement.

Did you complete the repair and/or replacement?

Go to Step 9

--

9

  1. Remove the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation.
  2. Have an assistant apply and release the park brake while you observe both of the brake caliper piston apply levers and the rear park brake cables for free and complete motion during both apply and release.

Did the caliper piston apply levers and the rear park brake cables exhibit free and complete motion during both apply and release of the park brake?

Go to Step 10

Go to Step 12

10

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.

Do the rear brakes have a significant amount of drag?

Go to Step 11

Go to Step 12

11

  1. Release the park brake.
  2. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag.

Did the rear brakes exhibit a significant reduction in the amount of drag?

Go to Step 18

Go to Step 12

12

  1. Disconnect the rear park brake cables from the front cable. Refer to Parking Brake Rear Cable Replacement.
  2. Disconnect the rear park brake cables from the brake caliper piston apply levers. Refer to Parking Brake Rear Cable Replacement.
  3. Inspect the rear park brake cables for free movement.
  4. Apply and release the brake caliper piston apply levers. Observe for the following:
  5. • Free motion of the piston apply levers during apply and free and complete return to the stops when released
    • Free movement of the caliper pistons during apply and free return movement when released

Do any of the park brake cables checked require replacement?

Go to Step 14

Go to Step 13

13

Did the brake caliper piston apply levers move freely during apply and freely and completely return to the stops during release; and did the caliper pistons exhibit freedom of movement during apply and release?

Go to Step 20

Go to Step 19

14

Replace any of the park brake cables inspected that do not have free movement. Refer to Parking Brake Rear Cable Replacement.

Did you complete the replacement?

Go to Step 15

--

15

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.

Do the rear brakes have a significant amount of drag?

Go to Step 16

Go to Step 17

16

  1. Release the park brake.
  2. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag.

Did the rear brakes exhibit a significant reduction in the amount of drag?

Go to Step 18

Go to Step 17

17

  1. Disconnect the rear park brake cables from the front cable. Refer to Parking Brake Rear Cable Replacement.
  2. Disconnect the rear park brake cables from the brake caliper piston apply levers. Refer to Parking Brake Rear Cable Replacement.
  3. Have an assistant apply and maintain the caliper piston apply lever to apply the caliper piston.
  4. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.
  5. Repeat steps 3 and 4 for the other side of the vehicle.
  6. Release the caliper piston apply levers.
  7. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag.

Did the brake calipers apply and release properly?

Go to Step 18

Go to Step 19

18

  1. Reconnect the rear park brake cables if they have been disconnected. Refer to Parking Brake Rear Cable Replacement.
  2. Grasp one of the rear park brake cables and pull downward to check the amount of tension on the park brake cable.
  3. The park brake cables should have a moderate amount of tension.

  4. Quickly release the rear cable and observe for a quick and complete return of the cable.
  5. Repeat steps 2 and 3 for the other rear park brake cable.

Did the park brake cables have a moderate amount of tension and exhibit a quick and complete return?

Go to Step 21

Go to Step 20

19

Replace the appropriate rear brake caliper. Refer to Rear Brake Caliper Replacement.

Did you complete the replacement?

Go to Step 21

--

20

Replace the park brake lever assembly. Refer to Parking Brake Lever Replacement. The front park brake cable and the park brake pedal are replaced as an assembly.

Did you complete the replacement?

Go to Step 21

--

21

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.
  3. Release the park brake.
  4. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag.

Did the park brake apply and release properly?

Go to Step 22

Go to Step 4

22

Install or connect any components that were removed or disconnected during diagnosis.

Did you complete the operation?

Park Brake System OK

Return to Symptom Table

--

Park Brake System Diagnosis Drum

Step

Action

Yes

No

DEFINITION: This diagnostic table is designed to diagnose ONLY the components of the PARK brake system in order to determine if the PARK brake system is operating properly. You will be directed by the appropriate Symptom table to go to other brake system diagnostic tables as appropriate.

1

Were you sent here from a Hydraulic Brake Symptom table?

Go to Step 4

Go to Step 2

2

Were you sent here from a Park Brake Symptom table?

Go to Step 4

Go to Step 3

3

Is the symptom related to the ability of the park brake system to hold and/or release?

Go to Diagnostic Starting Point - Park Brake

Go to Diagnostic Starting Point - Hydraulic Brakes

4

  1. Raise and support the vehicle with the rear axle supported by jack stands. Refer to Lifting and Jacking the Vehicle.
  2. With the park brake RELEASED, attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.

Do the rear brakes have a significant amount of drag?

Go to Step 11

Go to Step 5

5

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.

Do the rear brakes have a significant amount of drag?

Go to Step 6

Go to Step 7

6

  1. Release the park brake.
  2. Rotate the rear wheels to check the rear brakes for a significant reduction in the amount of drag.

Did the rear brakes exhibit a significant reduction in the amount of drag?

Go to Step 20

Go to Step 11

7

Visually check the park brake cable connections and the cables that are accessible on the UNDERSIDE of the vehicle for disconnections and/or damage.

Were any of the park brake cables disconnected and/or damaged?

Go to Step 8

Go to Step 9

8

Reconnect or replace the park brake cables as necessary. Refer to Parking Brake Rear Cable Replacement.

Did you complete the repair and/or replacement?

Go to Step 9

--

9

Check the adjustment of the park brake. Refer to Parking Brake Adjustment.

Was the park brake adjusted properly?

Go to Step 11

Go to Step 10

10

Adjust the park brake. Refer to Parking Brake Adjustment.

Were you able to attain adjustment of the park brake?

Go to Step 16

Go to Step 11

11

Caution: Do not depress the brake pedal with the brake rotors and/or the brake drums removed, or with the brake calipers repositioned away from the brake rotors, or damage to the brake system may result.

  1. Remove the brake drums. Refer to Brake Drum Replacement.
  2. Inspect the park brake hardware for loose, damaged, broken or missing components. Refer to Park Brake Hardware Inspection.
  3. Check the drum brake adjusters for a seized condition.

Does the park brake hardware and/or the park brake adjusters require replacement?

Go to Step 12

Go to Step 13

12

  1. Replace park brake hardware components as necessary. Refer to Brake Shoe Replacement.
  2. Replace the drum brake adjusting hardware as necessary. Refer to Drum Brake Adjusting Hardware Replacement.

Did you complete the replacement?

Go to Step 13

--

13

Have an assistant apply and release the park brake, while you observe the park brake cables for free movement.

Did the park brake cables move freely?

Go to Step 14

Go to Step 17

14

Check the adjustment of the park brake. Refer to Parking Brake Adjustment.

Was the park brake adjusted properly?

Go to Step 16

Go to Step 15

15

Adjust the park brake. Refer to Parking Brake Adjustment.

Were you able to attain adjustment of the park brake?

Go to Step 16

Go to Step 25

16

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.
  3. Release the park brake.
  4. Rotate the rear wheels to check the rear brakes for a significant reduction of drag.

Did the park brake apply and release properly?

Go to Step 27

Return to Symptom Table

17

Disconnect the park brake cable connections that are accessible on the UNDERSIDE of the vehicle one at a time and check each cable for free movement.

Do any of the park brake cables accessible on the underside of the vehicle require replacement?

Go to Step 18

Go to Step 19

18

Replace any of the park brake cables that do not have free movement - not releasing properly. Refer to Parking Brake Rear Cable Replacement.

Did you complete the replacement?

Go to Step 23

--

19

Replace the park brake lever assembly - not releasing properly. Refer to Parking Brake Lever Replacement.

Did you complete the replacement?

Go to Step 24

--

20

Check the adjustment of the park brake. Refer to Parking Brake Adjustment.

Is the park brake adjusted properly?

Go to Step 27

Go to Step 21

21

Adjust the park brake. Refer to Parking Brake Adjustment.

Were you able to attain adjustment of the park brake system?

Go to Step 26

Go to Step 22

22

  1. Remove the brake drums, if they have not yet been removed. Refer to Brake Drum Replacement.
  2. Check the drum brake adjusters for a seized condition.
  3. Replace the drum brake adjusting hardware as necessary.

Refer to Drum Brake Adjusting Hardware Replacement.

Did you find and correct a condition?

Go to Step 23

Go to Step 25

23

Adjust the park brake. Refer to Parking Brake Adjustment.

Were you able to attain adjustment of the park brake system?

Go to Step 26

Go to Step 25

24

Adjust the park brake. Refer to Parking Brake Adjustment.

Were you able to attain adjustment of the park brake system?

Go to Step 26

Return to Symptom Table

25

  1. Replace the component that is used to adjust the park brake system. Refer to Parking Brake Lever Replacement.
  2. Adjust the park brake. Refer to Parking Brake Adjustment.

Did you complete the replacement and adjustment?

Go to Step 26

Return to Symptom Table

26

  1. Apply the park brake.
  2. Attempt to rotate the rear wheels to check the rear brakes for a significant amount of drag.
  3. Release the park brake.
  4. Rotate the rear wheels to check the rear brakes for a significant reduction of drag.

Did the park brake apply and release properly?

Go to Step 27

Return to Symptom Table

27

Install or connect any components that were removed or disconnected during diagnosis.

Did you complete the operation?

Park Brake System OK

Return to Symptom Table

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