GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

DEFINITION: Brake system does not fully release or has delayed release; vehicle motion may be hindered by brake system without applying brakes.

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

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

Go to Step 5

Go to Step 7

5

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 6

Go to Step 8

6

  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 and heat spots.
  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

7

  1. Inspect the drum brake system, if equipped, for the following conditions:
  2. • Improper adjustment
    • Weak or damaged return spring or springs
    • Distorted or damaged linings
    • Out of round or damaged drum
    • Weak or damaged hold down spring or springs
    • Lack of lubrication on backing plate
    • Distorted or damaged backing plate
  3. Adjust, repair or replace components as necessary. Refer to Drum Brake System Diagnosis.

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.

Did you find and correct a condition?

Go to Step 15

Go to Step 9

9

  1. Inspect the disc brake system for the following conditions:
  2. • Binding, incorrectly installed or missing caliper hardware and/or lining hardware--ensure free movement of linings and of caliper, if equipped with sliding type caliper.
    • Lack of lubrication or excessive corrosion on metal to metal contact surfaces
    • Distorted or damaged linings
    • Damaged or excessively worn caliper hardware and/or lining hardware
    • Bent or damaged caliper or mounting component
  3. Adjust, repair or replace components as necessary. 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

  1. Inspect the pushrod for improper positioning and/or damage. Correctly position or replace the pushrod if necessary.
  2. Inspect the brake pedal assembly for damage and replace if necessary.

Did you complete the repair or replacement?

Go to Step 15

--

12

  1. For vacuum boost systems, disconnect the vacuum check valve from the booster to relieve vacuum reserve.
  2. Separate the master cylinder from the brake booster. Do not disconnect any brake pipes.
  3. 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

  1. Inspect the hydraulic brake system for the following conditions:
  2. • Improper operation of wheel cylinder pistons, if equipped
    • Improper operation of caliper pistons
    • Contaminated brake fluid
    • Internally damaged flexible brake hoses; hindering brake release
    • Damaged or improperly operating master cylinder
  3. Adjust, repair or replace components as necessary. 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