Hydraulic System: Description and Operation

Hydraulic Brake Actuation

CAUTION: Blistering or swelling of rubber brake components may indicate contamination of the brake fluid by a petroleum based substance. If contaminated rubber components in the hydraulic brake system are found, new components must be installed, and the entire hydraulic brake system must be flushed with dean brake fluid to prevent recontamination.

This vehicle is equipped with a brake pedal actuated dual brake system. The system consists of the following:
^ power brake booster
^ brake master cylinder
^ front disc brake calipers
^ rear disc brake calipers
^ rear drum brake cylinders
^ brake tubes and hoses
^ Anti-Lock Brake System (ABS) components

The dual ABS hydraulic system is diagonally split, with the LH front and RH rear making up one circuit and the RH front and LH rear making up the other circuit.

Brake Fluid

WARNING: Use of any other than approved DOT 3 or DOT 4 brake fluid will cause permanent damage to brake components and will render the brakes inoperative.

WARNING: Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, Bush eyes with running water for 15 minutes. Get medical attention irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately. CAUTION: Brake fluid is harmful to painted or plastic surfaces. Brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.

Use clean, fresh Ford High Performance DOT 3 Motor Vehicle Brake Fluid C6AZ-19542-AB or equivalent DOT 3 fluid meeting Ford specification ESA-M6C25-A. If DOT 3 is not available, use Ford High Performance DOT 4 Brake Fluid meeting Ford specification SAE-J-1704.
^ Do not reuse brake fluid drained or bled from the system.
^ Do not use brake fluid that has been stored in an open container.
^ Do not use contaminated brake fluid.

Brake Master Cylinder
The brake master cylinder is a dual piston type. The brake master cylinder operates as follows:
^ When the brake pedal is depressed, pressure is applied by mechanical linkage to the primary and secondary piston.
^ Brake master cylinder pistons apply hydraulic pressure to the two opposed hydraulic circuits.
^ ABS brake master cylinder will not be overhauled, due to internal adjustments which require extensive special tools and fixtures. Service is made by installing a new master cylinder only.

The brake master cylinder consists of:
^ brake master cylinder reservoir
^ brake master cylinder body

Brake Master Cylinder Reservoir

NOTE: Whenever the brake master cylinder reservoir is removed from the brake master cylinder, new grommets must be installed.

The brake master cylinder reservoir:
^ is mounted to the brake master cylinder.
^ holds fluid supply for each brake master cylinder hydraulic piston.
^ provides visual fluid level markings.
^ contains the brake master cylinder fluid level sensor.
Brake Tubes and Hoses

CAUTION: Never use copper tubing. It is subject to fatigue, cracking and corrosion, which could result in brake tube failure.

Double wall steel tubing is used throughout the brake hydraulic system. All brake tube fittings must be correctly double flared to provide strong leakproof connections. When bending tubing to fit the underbody or rear axle contours, be careful not to kink or crack the tube.
If a section of brake tube is damaged, an entire new section must be installed with a tube of the same type, size, shape and length.
When installing new hydraulic brake tubing, hoses, or connectors, tighten all connections securely. After installation, bleed the brake system.
The wet appearance on the outer cover of rubber brake hoses is called "sweating." This is a normal condition for neoprene rayon braid hose and is not a sip of leakage or cause for the installation of a new hose.