1995 Mercury Grand Marquis Brake Service (ONLINE REPAIR MANUALS)

Remove wheels and inspect brake disc, caliper and linings. The wheel bearings should be inspected at this time and repacked if necessary. Do not get any grease on the linings.

If the caliper is cracked or fluid leakage through the casting is evident, it must be replaced as a unit.

Should it become necessary to remove the caliper when installing new parts, clean all parts in alcohol, then wipe dry using lint-free cloths. Using an air hose, blow out drilled passages and bores. Inspect dust boots for punctures or tears. If punctures or tears are evident, install new boots during assembly.

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Vacuum Assist Diaphragm Type

The vacuum assist diaphragm assembly multiplies the force exerted on the master cylinder piston in order to increase the hydraulic pressure delivered to the wheel cylinders while decreasing the effort necessary to obtain acceptable stopping performance.

Vacuum assist units get their energy by opposing engine vacuum to atmospheric pressure. A piston, cylinder and flexible diaphragm utilize this energy to provide brake assistance. The diaphragm is balanced with engine vacuum until the brake pedal is depressed, allowing atmospheric pressure to unbalance the u...

Disc brake service is extremely critical due to the close tolerances required in machining the brake disc to ensure proper brake operation.

Maintaining close control of the shape of the rubbing surfaces is necessary to prevent brake roughness. In addition, the surface finish must be non-directional and maintained at a micro-inch finish. This is necessary to avoid pulls and erratic performance, and to promote long lining life and equal lining wear of both the lefthand and righthand brakes.

Do not attempt to refinish the rubbing surfaces unless precision equipment, ...

Brake Roughness

Thickness Variation

The most common cause of brake chatter on disc brakes is a variation in thickness of the disc. If roughness or vibration is encountered during highway operation or if pedal pumping is experienced at low speeds, the disc may have excessive thickness variation. To inspect for this condition, measure the disc at 12 points with a micrometer at a radius approximately one inch from edge of disc. If thickness meas...

Master Cylinder

Except Capri, Escort, Sable, Taurus & Tracer

• On models equipped with ABS, depress brake pedal several times to exhaust all vacuum in the system.
• On all models, disconnect brake lines from master cylinder, then all necessary electrical connectors.
• On models equipped with ABS, disconnect hydraulic control unit supply hose at master cylinder. Secure hose in a position to prevent brake fluid loss.
• On all models, remove nuts retaining master cylinder to brake booster.
• Remove master cylinder.
• Reverse procedure to install. After installation is complete, fill master cyli...

Brake Roughness

The most common cause of brake chatter on disc brakes is a variation in thickness of the disc. If roughness or vibration is encountered during highway operation or if pedal pumping is experienced at low speeds, the disc may have excessive thickness variation. To inspect for this condition, measure the disc at 12 points with a micrometer at a radius approximately one inch from the edge of the disc. If t...