Preliminary Checks

NOTE: Base brake components consist of the brake shoes, caliper pads, calipers, wheel cylinders, brake drums, rotors, brake lines, master cylinder, booster, and parking brake components. Brake diagnosis involves determining if the problem is related to a mechanical, hydraulic, or vacuum operated component. The first diagnosis step is the preliminary check.

1. Check condition of tires and wheels. Damaged wheels and worn, damaged, or underinflated tires can cause pull, shudder, vibration, and a condition similar to grab.

2. If complaint was based on noise when braking, check suspension components. Jounce front and rear of vehicle and listen for noise that might be caused by loose, worn or damaged suspension or steering components.

3. Inspect brake fluid level and condition. Note that the front disc brake reservoir fluid level will decrease in proportion to normal lining wear. Also note that brake fluid tends to darken over time. This is normal and should not be mistaken for contamination.

a. If fluid level is abnormally low, look for evidence of leaks at calipers, wheel cylinders, brake lines, and master cylinder.

b. If fluid appears contaminated, drain out a sample. System will have to be flushed if fluid is separated into layers, or contains a substance other than brake fluid. The system seals and cups will also have to be replaced after flushing. Use clean brake fluid to flush the system.

4. Check parking brake operation. Verify free movement and full release of cables and pedal. Also note if vehicle was being operated with parking brake partially applied.

5. Check brake pedal operation. Verify that pedal does not bind and has adequate free play. If pedal lacks free play, check pedal and power booster for being loose or for bind condition. Do not road test until condition is corrected.

6. If components checked appear OK, road test the vehicle.
Road Test