Brake System Troubleshooting

Before concluding that the brake system is faulty, check the tire condition and inflation pressure, vehicle loading evenness, and front wheel alignment angles.

Vehicle pulls to one side during braking
1 Incorrect tire pressure (refer to Chapter Maintenance and Tune-Up).
2 Front wheel alignment out of specification.
3 Wheels of different sizes installed on the same axle (front or rear).
4 Brake lines obstructed (refer to Chapter Brakes).
5 One or more brake units faulty (refer to Chapter Brakes).
6 Suspension component fasteners loose (refer to Chapter Suspension and Steering).
7 Caliper or brake backing plate bolts loose (refer to Chapter Brakes).
8 Brake pads/shoes worn, damaged or contaminated with oil on one side of the vehicle (refer to Chapters Maintenance and Tune-Up and Brakes).
9 Caliper piston/wheel cylinder piston seized or binding in one of the brake units (refer to Chapters Maintenance and Tune-Up and Brakes).
10 Brake pads/shoes with different friction material types installed on opposite sides of the vehicle (refer to Chapters Maintenance and Tune-Up and Brakes).
11 Worn or damaged steering linkage or suspension components (refer to Chapters Maintenance and Tune-Up and Suspension and Steering).

Noise during braking (grinding or high-pitched squeal)
1 Brake pad friction material worn - noise produced by pad wear indicators (refer to Chapters Maintenance and Tune-Up and Brakes).
2 Brake disc/drum damaged by corrosion - usually after the vehicle has been parked for a long time (refer to Chapters Maintenance and Tune-Up and Brakes).
3 Foreign object (e.g., stone) lodged between disc and brake backing plate (refer to Chapters Maintenance and Tune-Up and Brakes).

Vibration felt in brake pedal during braking
1 Excessive lateral runout of brake disc (refer to Chapter Brakes).
2 Brake pads unevenly worn (refer to Chapter Brakes).
3 Brake disc faulty (refer to Chapter Brakes).

Excessive brake pedal travel
1 Local malfunction in the brake system (refer to Chapter Brakes).
2 Brake fluid level in the master cylinder reservoir low (refer to Chapters Maintenance and Tune-Up and Brakes).
3 Air in the hydraulic system (refer to Chapters Maintenance and Tune-Up and Brakes).
4 Master cylinder faulty (refer to Chapter Brakes).
5 Brake vacuum booster faulty (refer to Chapter Brakes).

Spongy brake pedal when depressed
1 Air in the hydraulic system (refer to Chapters Maintenance and Tune-Up and Brakes).
2 Flexible brake hoses deteriorated with age (refer to Chapters Maintenance and Tune-Up and Brakes).
3 Master cylinder mounting bolts loose (refer to Chapter Brakes).
4 Master cylinder faulty (refer to Chapter Brakes).

Excessive force required on brake pedal to stop the vehicle
1 Brake vacuum booster faulty (refer to Chapter Brakes).
2 Local malfunction in the brake system (refer to Chapter Brakes).
3 Brake pads/shoes excessively worn (refer to Chapter Brakes).
4 Caliper piston(s)/wheel cylinder seized (refer to Chapter Brakes).
5 Brake pad/shoe friction material contaminated with oil or grease (refer to Chapters Maintenance and Tune-Up and Brakes).
6 New brake pads/shoes recently installed and not yet bedded in.

Vibration transmitted to brake pedal or steering wheel during braking
1 Excessive brake disc runout/brake drum distortion (refer to Chapters Maintenance and Tune-Up and Brakes).
2 Brake pads/shoes worn (refer to Chapters Maintenance and Tune-Up and Brakes).
3 Caliper/brake backing plate bolts loose (refer to Chapter Brakes).
4 Suspension, steering linkage or mounting bushings worn (refer to Chapters Maintenance and Tune-Up and Suspension and Steering).

Brake pedal pulsation when depressed during hard braking
Normal ABS operation (refer to Chapter Brakes).

Brakes binding, or uneven braking force from brake units
1 Brake light switch adjustment incorrect (refer to Chapter Brakes).
2 Master cylinder faulty (refer to Chapter Brakes).
3 Brake lines obstructed (refer to Chapter Brakes).
4 Parking brake adjustment incorrect (refer to Chapter Brakes).
5 Brake caliper piston(s)/wheel cylinder seized or binding (refer to Chapter Brakes).

Braking is uneven
1 Proportioning valve faulty (refer to Chapter Brakes).
2 Brake vacuum booster faulty (refer to Chapter Brakes).
3 Brake pedal seized (refer to Chapter Brakes).

Rear wheels lock during normal braking
1 Brake shoe friction material contaminated (refer to Chapters Maintenance and Tune-Up and Brakes).
2 Rear brake discs/drums distorted (refer to Chapters Maintenance and Tune-Up and Brakes).

Brake pedal drops to floor without resistance
1 Brake fluid level in master cylinder reservoir low, or leakage past caliper pistons/wheel cylinder pistons (refer to Chapter Brakes).
2 Brake lines damaged or their fittings loose (refer to Chapter Brakes).

Parking brake does not hold the vehicle properly
Parking brake linkage adjustment incorrect (refer to Chapter Brakes).