Grand Prix V6-191 3.1L VIN M SFI (1998)
Brake Master Cylinder: Description and Operation
IMPORTANT:
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Replace all of the components that are included in the repair kits used to service this master cylinder.
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Lubricate the rubber parts with clean brake fluid in order to ease assembly.
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Do not use lubricated compressed air on the brake parts. This action may cause damage to the rubber components.
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If you remove or disconnect any hydraulic part, you may have to bleed all or part of the brake system.
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The specified torque values are for dry, non-lubricated fasteners.
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Perform the service operations on a clean bench that is free from all mineral oil materials.
This master cylinder is a composite design with a plastic reservoir and an aluminum body. The master cylinder is used in a diagonally split system. In
this system, one front and one diagonally rear brake is served by the primary piston (8), and the opposite front and rear brakes are served by the
secondary piston (10).
The master cylinder incorporates the functions of a standard dual master cylinder. The master cylinder also has a fluid level sensor. The proportioning
valves are designed to provide better front-to-rear braking balance with a heavy brake application.
PROPORTIONING VALVES
IMPORTANT: Do not wash the proportioning valve in any cleaning solution. The internal components are prelubricated with a special grease.
The proportioning valves are located in the rear brake lines on each side of the fuel tank. The proportioning valves thread into the rear brake lines. The
proportioning valves proportion the brake fluid to each caliper or wheel cylinder after a predetermined amount of pressure is reached. The
proportioning valves limit outlet pressure to the rear brakes after the brakes meet a predetermined inlet pressure. The proportioning valves limit
pressure when less apply force is needed in order to obtain optimum breaking. The proportioning valves prevent rear wheel lock-up on vehicles that
do not have heavy rear wheel loads.
FLUID LEVEL SENSOR
The compact master cylinders are equipped with a fluid level sensor. The sensor switch is located in the inboard side of the reservoir. The sensor
activates the BRAKE warning lamp if the fluid level is low. The BRAKE warning lamp turns off when the fluid level is corrected.
ANTILOCK BRAKE SYSTEM
The antilock brake system uses an amber ANTILOCK lamp.
The lamp is located in the instrument panel cluster. Ensure that the lamp exhibits the following conditions under normal conditions:
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The amber ANTILOCK lamp turns ON when the ignition is turned to the RUN position, prior to starting the engine.
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Ensure that the lamp is OFF when the engine starts. The operation of the warning lamp is an important part of the antilock brake system
diagnosis. If the warning lamp turns ON when you are driving the vehicle, this indicates a malfunction.
SUBSTANDARD OR CONTAMINATED BRAKE FLUID
CAUTION:
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Brake fluid may Irritate eyes and skin. In case of contact, take the following actions:
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Eye contact rinse thoroughly with water.
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Skin contact wash with soap and water.
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if Ingested consult a physician Immediately.
CAUTION: Use only SUPREME 11 (GM PN# 12377967J DOT 3 brake fluid from a clean, sealed container. Do not use fluid from an open container
that may be contaminated with water. Improper or contaminated fluid could result In damage to components, or loss of braking, with possible Injury.
