Abnormal Conditions

NOTE: Prior to performing any diagnosis, make sure the brake system warning indicator is functional.

Changes in brake pedal feel or travel are indicators that something could be wrong in the brake system. The diagnostic procedure and techniques use brake pedal feel, warning indicator illumination and low brake fluid level as indicators in diagnosing brake system concerns. The following conditions are considered abnormal and indicate that the brake master cylinder is in need of repair.
- Brake pedal goes down fast. This could be caused by an external or internal leak.
- Brake pedal eases down slowly. This could be caused by an external or internal leak.
- Brake pedal is low and/or feels spongy. This condition may be caused by no fluid in the brake master cylinder reservoir, reservoir cap vent holes clogged or air in the hydraulic system.
- Brake pedal effort is excessive. This may be caused by a bind or obstruction in pedal/linkage, clogged fluid control valve or insufficient booster vacuum.
- Rear brakes lock up during light pedal force. This may be caused by grease or fluid on brake shoes and linings, damaged brake shoes and linings, incorrectly adjusted parking brakes, or damaged/contaminated brake pressure control valves.
- Brake pedal effort is erratic. This condition could be caused by brake booster malfunction, extreme caliper piston knock back or incorrectly installed brake shoes and linings.
- Brake warning indicator is ON. This may be caused by low fluid level, ignition wire routing too close to fluid level indicator assembly, or float assembly damage.