GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 Canyon Pickup - 4WD 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Braking Action Uneven - Front to Rear

Test Description

The number below refer to the step number on the diagnostic table:

  1. Suspension components that are not operating properly may cause a disturbance to the vehicle during application of the brake system.

Step

Action

Yes

No

DEFINITION: Braking action or stopping force sensitive or grabbing and/or more pronounced at the front or at the rear axle. Sensitive or grabbing brakes: Excessive brake jump-in force relative to brake pedal input.

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 hydraulic brake system for the following conditions.
    2. • Improper operation of wheel cylinder pistons, if equipped
    • Improper operation of caliper pistons
    • Kinked, pinched or damaged brake pipe or flexible brake hose
    • Brake fluid leak
    • Improperly functioning proportioning valve, if equipped
    • Improper operation of dynamic rear proportioning (DRP) system, if equipped
  2. Adjust, repair or replace components as necessary. Refer to Hydraulic Brake System Diagnosis.

Did you find and correct a condition?

Go to Step 7

Go to Step 3

3
  1. Inspect the disc brake system for the following conditions.
    2. • Contaminated linings
    • Glazed linings
    • Distorted, cracked or damaged linings
    • Excessively worn linings
    • Aftermarket linings
    • Damaged or excessively worn caliper hardware and/or lining hardware
    • Hard spots, heat checks, blueing discoloration of rotor friction surfaces
    • Glazed rotor friction surfaces
  2. Adjust, repair or replace components as necessary. Refer to Disc Brake System Diagnosis.

Did you find and correct a condition?

Go to Step 7

Go to Step 4

4
  1. Inspect the drum brake system, if equipped, for the following conditions.
    2. • Contaminated linings
    • Improper adjustment
    • Excessively worn or damaged linings
    • Weak or damaged return spring or springs
    • Excessively worn or damaged drums
    • Hard spots, heat checks, blueing discoloration of drum friction surface
    • Distorted or damaged backing plate
  2. Adjust, repair or replace components as necessary. Refer to Drum Brake System Diagnosis.

Did you find and correct a condition?

Go to Step 7

Go to Step 5

5

  1. Inspect the suspension system for the following conditions.
    2. • Loose suspension component connections
    • Excessively worn or damaged suspension components
  2. Adjust, repair or replace components as necessary. Refer to Diagnostic Starting Point - Suspension General Diagnosis.

Did you find and correct a condition?

Go to Step 7

Go to Step 6

6
  1. Inspect the brake assist system for the following conditions.
    2. • Binding, bent or damaged pedal pushrod, pedal, or pedal bracket
    • Damaged or improperly operating vacuum booster, if equipped
    • Damaged or improperly operating hydraulic booster, if equipped
  2. Adjust, repair or replace components as necessary. Refer to Brake Assist System Diagnosis.

Did you find and correct a condition?

Go to Step 7

Go to Diagnostic Starting Point - Hydraulic Brakes

7
  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