GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

DEFINITION: Fluctuation or pulsation is felt through the brake pedal, steering wheel, seat, floor, and/or in the vehicle ONLY when braking.

1

Were you sent here from the Hydraulic Brake Symptom table?

Go to Step 2

Go to Diagnostic Starting Point - Hydraulic Brakes

2

  1. Inspect the disc brake system for the following conditions.
  2. • Excessive thickness variation of rotor friction surfaces
    • Excessive assembled lateral runout (LRO) of rotor friction surfaces
    • Hard spots, heat checks, blueing discoloration of rotor friction surfaces; possibly due to brake drag
    • Excessive corrosion of rotor friction surfaces; including red, gray or black oxidation
    • Loose, damaged or missing caliper or lining hardware
    • Bent or damaged caliper or mounting component
    • Excessive LRO of wheel hub/axle flange; due to damage and/or loose or excessively worn bearings
  3. Adjust, repair or replace components as necessary. Refer to Disc Brake System Diagnosis.

Did you find and correct a condition?

Go to Step 4

Go to Step 3

3

  1. Inspect the drum brake system, if equipped, for the following conditions.
  2. • Out of round or damaged drum
    • Excessive radial runout of drum friction surface
    • Hard spots, heat checks, blueing discoloration of drum friction surface; possibly due to brake drag
    • Bent or damaged drum
    • Excessive radial runout of wheel hub/axle flange; due to damage and/or loose or excessively worn bearings
  3. Adjust, repair or replace components as necessary. Refer to Drum Brake System Diagnosis.

Did you find and correct a condition?

Go to Step 4

Go to Diagnostic Starting Point - Hydraulic Brakes

4

  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