Component Tests and General Diagnostics
Brake System Inspection and TestInspect the brake system components listed. Repair or replace any parts that are leaking or damaged.
Brake System Test
Brake pedal sinks/fades when braking
1. Set the parking brake, and start the engine, then turn off the A/C switch. Allow the engine to warm up to normal operating temperature (radiator fan comes on twice).
2. Attach a 50 mm (2 in.) piece of masking tape along the bottom of the steering wheel, and draw a horizontal reference mark across it.
3. With the transmission in Neutral, press and hold the brake pedal lightly (about the same pressure needed to keep an A/T-equipped car from creeping), then release the parking brake.
4. While still holding the brake pedal, hook the end of the tape measure behind the brake pedal, then pull the tape up to the steering wheel, noting where the tape measure lines up with the reference mark you made on the masking tape.
5. Apply steady pressure to the brake pedal for 3 minutes.
6. Watch the tape measure.
^ If it moves less than 10 mm (3/8 in.), the master cylinder is OK.
^ If it moves more than 10 mm (3/8 in.), replace the master cylinder.