Master Cylinder Overhaul

CAUTION: Do not disturb or remove the screw which retains the primary spring to the secondary piston. This screw has been set to a predetermined height, and the performance of the master cylinder will be adversely affected if this setting is changed. An improperly adjusted screw may result in poor brake performance and possible personal injury.

Important: Reservoir cap and diaphragm can be inspected and/or serviced without removing the master cylinder from the vehicle.

REMOVE OR DISCONNECT
^ ABS hydraulic modulator/master cylinder.

DISASSEMBLE
1. Reservoir cap and diaphragm.
- Wipe reservoir cap clean before removing.

Inspect
- Reservoir cap and diaphragm for:
^ Cuts.
^ Cracks.
^ Nicks.
^ Deformation.
- Replace damaged parts.

2. Master cylinder reservoir. Refer to "MASTER CYLINDER RESERVOIR."
3. Proportioning valves. Refer to "PROPORTIONING VALVES."
4. Retainer while depressing primary piston.
- Take care not to damage the piston, bore, or retainer groove.
5. Apply low pressure, nonlubricated, compressed air into upper outlet port at blind end of bore (all other outlet ports plugged) to remove:
- Primary piston.
- Secondary piston.
- Spring.
- Spring retainer.
6. From secondary piston:
- Seals.
- Spring retainer.

Inspect
- Master cylinder bore for scoring or corrosion. Replace master cylinder if any of these conditions are found. No abrasives should be used in bore.

Clean
- All parts in clean, denatured alcohol.
- Dry with nonlubricated, compressed air.

ASSEMBLE
1. Lubricated seals and spring retainer onto secondary piston.
2. Spring and secondary piston into cylinder bore.
- To ease reassembly, lubricate with clean brake fluid.
3. Lubricated primary piston into cylinder bore.
4. Retainer while pressing primary piston.
5. Proportioning valves. Refer to PROPORTIONING VALVES.
6. Master cylinder reservoir. Refer to MASTER CYLINDER RESERVOIR.
7. Diaphragm into reservoir cap and install on reservoir.

INSTALL OR CONNECT
^ ABS hydraulic modulator/master cylinder.