1991 Mercury Colony Park Brake Service (ONLINE REPAIR MANUALS)

Pressure bleeding is recommended for all hydraulic brake systems.

The bleeding operation itself is fairly well standardized. First step in all cases is cleaning the dirt from the filler cap before removing it from the master cylinder. This should be done thoroughly.

Pressure bleeding is fastest because the master cylinder doesn't have to be refilled several times, and the job can be done by one man. To prevent air from the pressure tank getting into the lines, do not shake the tank while air is being added to the tank or after it has been pressurized. Set the tank in the required ...

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 de...

Complaints about power brake operation should be handled as if two separate systems exist. Check for faults in the hydraulic system first. If it is satisfactory, start inspecting the power brake circuit. For a quick check of proper power unit operation, press the brake pedal firmly and then start the engine. The pedal should fall away slightly and less pressure should be needed to maintain the pedal in any position.

Another check begins with installation of a suitable pressure gauge in the brake hydraulic system. Take a reading with the engine off and the power unit not opera...

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 for installation of new parts, clean all parts in alcohol, wipe dry using lint free cloths. Using an air hose, blow out drilled passages and bores. Check dust boots for punctures or tears. If punctures or tears are evident, new boots should be installed upon re...

Servicing of disc brakes is extremely critical due to the close tolerances required in machining the brake disc to insure proper brake operation.

The maintenance of these close controls 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 close control of the rubbing surface finish is necessary to avoid pulls and erratic performance and promote long lining life and equal lining wear of both left and right brakes.

In light of the foregoing remarks, refinis...

Whenever new brake components are installed in the hydraulic system, it is recommended that the entire hydraulic system be thoroughly flushed with clean brake fluid.

It may sometime become necessary to flush out the system due to the presence of mineral oil, kerosene, gasoline, etc., which will cause swelling of rubber piston cups and valves so they become inoperative. The procedure is as follows:

Flushing is ...