Escort ZX2 L4-2.0L DOHC VIN 3 (2000)
Brake Master Cylinder: Testing and Inspection
NORMAL CONDITIONS
The following conditions are considered normal and are not indications that the brake master cylinder is in need of repair or replacement.
Condition 1. During normal operation of the brake master cylinder, the brake fluid level in the brake master cylinder reservoir will fall during brake
application and rise during release. The net brake fluid level will remain unchanged after brake application and release.
Condition 2. A trace of brake fluid may exist on the power brake booster shell below the brake master cylinder mounting flange. This is the result of
the normal internal lubricating action of the brake master cylinder.
Condition 3. Brake fluid level will decrease as the brake shoes and linings wear.
ABNORMAL CONDITIONS
Changes in brake pedal feel and travel are indications that a brake system malfunction exists. Refer to the Symptom Chart at Brakes and Traction
Control/Testing and Inspection for abnormal condition diagnosis.
BYPASS CONDITION TEST
1. Check the brake hydraulic system for leaks or insufficient brake fluid. Repair as necessary.
2. Observe the brake fluid level in the brake master cylinder reservoir as the brake pedal is slowly pressed and quickly released. If the brake fluid
level rises when the brake pedal is pressed and drops when the brake pedal is released, but the net brake fluid level remains unchanged, the brake
master cylinder is bypassing. Repair or replace the brake master cylinder.
NON-PRESSURE EXTERNAL LEAKS
A low brake fluid level in the brake master cylinder reservoir may be caused by the following non-pressure external leaks:
Type 1. An external leak may exist at the brake master cylinder filler cap due to improper position of the cap, cap gasket, or cap gasket deterioration.
Type 2. An external leak may exist at the brake master cylinder mounting flange due to internal seal failure. Repair or replace the brake master
cylinder.
Type 3. An external leak may exist at the base of the brake master cylinder reservoir due to deteriorated reservoir mounting seals. Repair or replace
the brake master cylinder.
COMPENSATOR PORT CHECK
The purpose of the compensator ports in the brake master cylinder is to:
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Supply additional brake fluid from the brake master cylinder reservoir required by the brake system due to brake shoe and lining wear.
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Allow brake fluid to return to the brake master cylinder reservoir when the brakes are released. The returning brake fluid will create a slight
turbulence in the brake master cylinder reservoir. This is a normal condition and indicates that the compensator ports are not clogged.
Clogged compensator ports may cause the brakes to "hang-up" or not fully release. If clogged compensator ports are suspected, proceed as follows:
1. Raise and support the vehicle.
2. With the brakes released, attempt to rotate each wheel. If an excessive amount of brake drag exists, continue with the test. If an excessive amount
of brake drag exists at only one wheel, it indicates a possible seized rear disc brake caliper, front disc brake caliper, rear wheel cylinder, or parking
brake component. Repair or replace components as necessary.
3. Check the Brake Pedal Position (BPP) switch adjustment, and brake pedal free play to verify that the brake pedal is not partially applied.
4. Loosen the nuts attaching the brake master cylinder to the power brake booster and pull the brake master cylinder away from the power brake
booster.
5. Repeat Steps 1 and 2. If the brake drag disappears, the power brake booster is binding and must be replaced. If the brake drag continues, the brake
master cylinder is binding and must be replaced.