OVERHAUL

1972–84 Vehicles

1. Remove the master cylinder.
2. Clean the outside of the cylinder thoroughly and drain the fluid.
3. On models through 1975, remove the dust cover.
4. Pry out the piston stop ring and remove the stop washer.
5. Remove the piston, piston cup and spring from the cylinder.
6. On all models except the 1976–78 B1800, carefully remove and disassemble the one-way valve.
7. Clean all parts thoroughly using clean brake fluid.
8. Discard any worn, damaged or misshapen parts.
9. Check the piston-to-bore clearance. Clearance should be 0.15mm (0.0059 in.). If clearance exceeds this figure, replace the unit.
10. If the cylinder bore is lightly scored or brinnelled, it may be honed to restore the finish.
11. Assembly is the reverse of disassembly. Coat all parts with clean brake fluid prior to assembly. On 1976–78 B1800 models, be sure that the compensating port is open. Fill and bleed the system.

1986 Vehicles

1. Remove the master cylinder.
2. Using snapring pliers, press down on the piston and remove the snapring from the cylinder bore.
3. Remove the piston and secondary cup, primary cup protector, primary cup, return spring, reservoir and bushing.
4. The secondary piston and cup must be blown out with compressed air applied to the fluid pipe hole. Be careful to cover the bore opening with a heavy rag to catch the piston.
5. Inspect all parts for wear or damage. Clean all parts in clean brake fluid.
6. Assembly is the reverse of disassembly. Coat all parts with clean brake fluid prior to assembly.