GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 GL7 (Export) 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Hydraulic Brake Diagnostic System Check

Step

Action

Normal Result(s)

Abnormal Result(s)*

1

Inspect the master cylinder brake fluid level.

The brake fluid level is nominal.

The brake fluid is low. Refer to Master Cylinder Reservoir Filling .

2

Inspect the brake fluid reservoir cap seal for signs of swelling.

The brake fluid reservoir cap is not swollen.

The brake fluid reservoir cap is swollen. Replace all of the brake system rubber components an

  1. Flush the hydraulic brake system. Refer to Hydraulic Brake System Flushing .
  2. Replace all of the brake system rubber components.
  3. Flush the hydraulic brake system again. Refer to Hydraulic Brake System Flushing .

3
  1. Turn the ignition OFF.
  2. Ensure that the park brake is released.
  3. Start the engine.
  1. The brake warning indicator turns on while the engine is cranking.
  2. The brake warning indicator turns off after the engine starts.

The brake warning indicator does not turn on while the engine is cranking. Refer to BRAKE Indicator Inoperative .

The brake warning indicator stays on after the engine starts. Refer to BRAKE Indicator Always On .

4
  1. Shift the transmission into Park.
  2. Press the brake pedal firmly.
  1. The brake pedal moves steadily towards floor, approximately 50 mm (2 in).
  2. The brake pedal stops and is firm against the pressure.

The brake pedal moves more than 50 mm (2 in) towards the floor. Refer to Brake Pedal Excessive Travel .

The brake pedal is too soft and/or the brake pedal slowly moves all the way to the floor. Refer to Brake Pedal Travel Gradually Increases .

5

Release the brake pedal.

The brake pedal returns to the original position.

The brake pedal does NOT return to the original position.

6

Perform the brake system test. Refer to Brake System Testing .
    • The braking action starts immediately after applying the brakes.
    • The brakes operate smoothly and predictably. do not grab - brake pedal does not pulsate.
    • The steering wheel and the brake pedal do not shake (pulsate) while the brakes are applied.
    • The vehicle stops without high brake pedal effort.
    • The vehicle stops without pulling to one side.
    • The front and rear brakes apply evenly.
    • The brakes operate without excessive noise.
    • The brakes do not drag (stay engaged) after the brake pedal is released.
    • The braking action is delayed after applying the brakes. Refer to Brake System Slow Response .
    • The brakes operate aggressively with low pressure applied to the brake pedal.
    • The steering wheel or the brake pedal pulsate while the brakes are applied. Refer to Brake Pulsation .
    • The brake pedal effort is high or the vehicle is difficult to stop. Refer to Brake Pedal Excessive Effort to Stop .
    • The vehicle pulls to one side while braking. Refer to Braking Action Uneven - Side to Side .
    • The front or rear brakes operate unevenly. Refer to Braking Action Uneven - Front to Rear .
    • The brakes drag (stay engaged) after the brake pedal is released. Refer to Brake System Slow Release or Brakes Drag .