Master brake cylinder
1 – adapter with three tubes; 2 – adapter with two tubes; 3 – main brake cylinder; 4 – gasket; 5 – brake booster
Removal
1. Disconnect the electrical connector from the brake fluid reservoir.
2. Remove the brake fluid reservoir cap and use a syringe to pump out the brake fluid.
3. Mark the brake pipes that go to the master cylinder. Place a clean rag under the master cylinder. Unscrew the brake pipe mounting nuts and move the brake pipes away from the master cylinder. Close the ends of the pipes with the appropriate plugs.
4. Unscrew the mounting nuts and remove the master brake cylinder from the brake booster together with the gasket.
Repair
Brake Master Cylinder Parts (top without ABS, bottom with ABS)
1 – main brake cylinder housing; 2 – sealing ring; 3 – brake fluid reservoir mounting screw; 4 – cork; 5 – mesh filter; 6 – brake fluid reservoir; 7 – sealing ring; 8 – retaining ring; 9 – piston and spring No.1; 10 – piston and spring No.2; 11 – gasket; 12 – lock bolt; 13 – lock bolt; 14 – gasket; 15 – sealing ring; 16 – brake fluid reservoir mounting screw; 17 – cork; 18 – mesh filter; 19 – brake fluid reservoir; 20 – sealing ring; 21 – retaining ring; 22 – piston and spring No.1; 23 – piston and spring No.2; 24 – main brake cylinder housing
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1. Unscrew the tank mounting bolt.
2. Remove the brake fluid reservoir and O-rings.
3. Secure the master cylinder in a vice and, using a suitable drift, push the master cylinder pistons in until they stop and remove the lock bolt.
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4. Remove the retaining ring from the end of the master cylinder.
5. Remove the pistons and springs from the master cylinder housing.
6. Wash all the parts of the brake master cylinder in brake fluid and check the condition of the parts. Before installing the parts in the brake master cylinder, pre-lubricate them with clean brake fluid.
7. Install the pistons with springs into the master cylinder, move them forward until they stop and tighten the lock bolt.
8. Install a new snap ring into the rear of the master cylinder.
9. Install the brake fluid reservoir sealing bushings, reservoir and secure the reservoir with the screw.
10. Before installing the master cylinder, fill it with brake fluid and remove air by securing the master cylinder in a vice and closing the outlet holes of the master cylinder with threaded plugs.
11. Fill the reservoir with clean brake fluid.
12. Unscrew one plug and, by moving the piston in the master brake cylinder, squeeze the air out of it.
13. Before releasing the piston, screw the threaded plug back into place.
14. Repeat the bleeding operation until only clean brake fluid without air bubbles comes out of the hole. Repeat the bleeding operation from the master cylinder on the second outlet hole.
Installation
1. Install the master cylinder onto the brake booster struts and secure with nuts, hand tightening them at this stage.
2. Unscrew the threaded plugs from the master brake cylinder and screw the brake pipes into their place.
3. Finally tighten the brake master cylinder mounting nuts.
4. Remove air from the master brake cylinder that got there when installing the brake pipes. Press the brake pedal sharply, unscrew the nut securing the brake pipe to the master brake cylinder by half a turn with the pedal pressed. Continuing to press the pedal, force out the fluid in the system together with the air. After the pedal reaches the extreme forward position and the fluid stops leaking, tighten the nut securing the pipeline. Repeat these operations until air stops leaking from the master brake cylinder.