Dismantling master cylinder

Dismantling master cylinder

1. Refer to FIG 10:7 and remove the plunger and rubber boot from the cylinder body.
2. Using a pair of circlip pliers remove the plunger circlip.
3. Carefully slide off from the inside of the cylinder body the plunger, plunger seal, valve ring carrier, valve ring and the reaction spring.
4. Remove the stoplight pressure operated switch.
5. Remove the cylinder body stop plug and upper plug.
6. Carefully inspect the master cylinder inner surface and plunger outer surface to ensure that they have a mirrorlike finish and that the play between the two parts is not excessive. Any roughness present on the cylinder inner surface will necessitate renewing the complete assembly. Scoring or corrosion of the surface will quickly damage the rubber seals and can lead to leakage of fluid and consequent partial or complete brake failure. Check that the plunger return spring is not corroded or distorted.

Master cylinder reassembly

Ensure that the metal parts are clean. Dry off any solvent used for cleaning. Renew all the rubber seals as a matter of course. Wet the internal parts with clean brake fluid and reassemble them in the order shown in FIG 10:7.

Refitting the master cylinder

Carefully locate the master cylinder flange to the body panel ensuring that the pushrod 12 (see FIG 10:7) correctly locates in the plunger 9. Secure the master cylinder flange using the two nuts and spring washers. Refit the hydraulic pipes.

Remove the tapered wooden plug from the reservoir and bleed the system as described in Section 10:10. Apply the brakes hard for several minutes and inspect the master cylinder and hydraulic connections for leaks.