GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Were you sent here from the Hydraulic Brake Symptom table?

Go to Step 2

Go to Diagnostic Starting Point - Hydraulic Brakes

2

Is the vehicle equipped with an adjustable stop lamp switch and/or an adjustable cruise control release switch?

Go to Step 3

Go to Step 4

3

  1. Inspect the stop lamp switch for proper adjustment to ensure that the brake pedal is fully releasing.
  2. Inspect the cruise control release switch, if equipped, for proper adjustment to ensure that the brake pedal is fully releasing.

Did you find and correct a condition?

Go to Step 15

Go to Step 4

4

Inspect the drum brake system, if equipped, for proper operation. Refer to Drum Brake System Diagnosis .

Did you find and correct a condition?

Go to Step 15

Go to Step 5

5

Is the vehicle equipped with a drum-in-rotor type of park brake system?

Go to Step 6

Go to Step 8

6

Ensure the park brake shoes are not adjusted too tightly, possibly causing drag under certain conditions.

Are the park brake shoes adjusted too tightly?

Go to Step 7

Go to Step 8

7

  1. Clean and inspect the park brake shoes for excessive wear and/or damage.
  2. Inspect the drum portion of the rotors for excessive wear, blueing discoloration, heat spots, and excessive radial runout.
  3. If any of these conditions are present, replace the affected components.
  4. Adjust the park brake system.

Did you find and correct a condition?

Go to Step 15

Go to Step 8

8

Inspect the park brake system for proper operation. Refer to Park Brake System Diagnosis in Park Brake.

Did you find and correct a condition?

Go to Step 15

Go to Step 9

9

Inspect the disc brake system for proper operation. Refer to Disc Brake System Diagnosis .

Did you find and correct a condition?

Go to Step 15

Go to Step 10

10

  1. Separate the brake booster pushrod from the brake pedal.
  2. Inspect the brake corners to determine if the brake drag condition is still present.

Do the brake corners still exhibit the brake drag condition?

Go to Step 12

Go to Step 11

11

Replace the brake pedal assembly.

Did you complete the replacement?

Go to Step 15

--

12

  1. Separate the master cylinder from the brake booster. Do not disconnect any brake pipes.
  2. Inspect the brake corners to determine if the brake drag condition is still present.

Do the brake corners still exhibit the brake drag condition?

Go to Step 14

Go to Step 13

13

Replace the brake booster assembly.

Did you complete the replacement?

Go to Step 15

--

14

Inspect the hydraulic brake system for proper operation. Refer to Hydraulic Brake System Diagnosis .

Did you find and correct a condition?

Go to Step 15

Go to Diagnostic Starting Point - Hydraulic Brakes

15

  1. Install or connect components that were removed or disconnected during diagnosis.
  2. Road test the vehicle in order to confirm proper operation. Refer to Brake System Vehicle Road Test .

Is the condition still present?

Go to Step 2

System OK