GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Hydraulic Brake Diagnostic System Check performed?

--

Go to Step 2

Go to Hydraulic Brake Diagnostic System Check

2

Inspect the brake pedal assembly for the following:

    • Bent or misaligned components
    • Binding or interference between the pedal and booster input rod

Are the components misaligned or binding?

--

Go to Step 3

Go to Step  4

3

Repair or replace the cause of misalignment, interference or binding.

Is the repair complete?

--

Go to Hydraulic Brake Diagnostic System Check

--

4

Inspect the disc brake pads and brake shoe linings for the following:

    • Excessive wear
    • Uneven wear
    • Abuse
    • Glazing
    • Contaminated lining material
    • Incorrect lining material

Refer to Brake Pad Inspection in Disc Brakes.

Do any of the above conditions exist?

--

Go to Step  5

Go to Step  6

5

Replace the brake linings. Refer to Brake Pads Replacement in Disc Brakes, or Brake Shoe Replacement in Drum Brakes.

Is the repair complete?

--

Go to Hydraulic Brake Diagnostic System Check

--

6

Inspect the brake rotor for the following:

    • Hot spots
    • Scored rotor surface
    • Grooved rotor surface

Do any of the above conditions exist?

--

Go to Step  7

Go to Step  8

7

  1. Refinish the brake rotor. Refer to Brake Rotor Refinishing in Disc Brakes.
  2. If refinishing the brake rotor results in a thickness that is less than the thinnest (Refinishing) thickness, replace the rotor. Refer to Brake Rotor Replacement in Disc Brakes.

Is the repair complete?

--

Go to Hydraulic Brake Diagnostic System Check

--

8

Inspect the Vacuum Brake Booster for leaks.

Is the Vacuum Brake Booster leaking?

--

Go to Step  9

Go to Step  10

9

Replace the Vacuum Brake Booster. Refer to Power Vacuum Brake Booster Replacement .

Is the repair complete?

--

Go to Hydraulic Brake Diagnostic System Check

--

10

Check the master cylinder outlet ports for restricted passages. Refer to Hydraulic Brake System Bleeding .

Are the outlet ports restricted?

--

Go to Step  11

Go to Step  12

11

  1. Replace the master cylinder. Refer to Master Cylinder Replacement .
  2. Flush the hydraulic brake system. Refer to Hydraulic Brake System Flushing .

Is the repair complete?

--

Go to Hydraulic Brake Diagnostic System Check

--

12

Check the brake pipes and hoses for the following:

    • Low fluid or no fluid output
    • Spurting of fluid while pressing the brake pedal
    • Particles suspended in the fluid

Refer to Hydraulic Brake System Flushing .

Do any of the above conditions exist?

--

Go to Step  13

Go to Step  14

13

  1. Determine the area of the restriction. This will involve the disassembly of individual brake lines and checking for low or no fluid output.
  2. Flush the individual brake line or hose. Refer to Hydraulic Brake System Flushing .
  3. If the restriction cannot be removed, replace the brake hose or pipe as necessary. Refer to Front Brake Hose Replacement , Rear Brake Hose Replacement or ISO Flares Replacement .
  4. Flush the hydraulic brake system. Refer to Hydraulic Brake System Flushing .

Is the repair complete?

--

Go to Hydraulic Brake Diagnostic System Check

--

14

Verify proper brake system operation.

Does the original condition still exist?

--

Verify customer complaint. Begin the diagnosis again. Go to Step 1

System OK