Note: Before starting work, refer to the warning at the beginning of Section 2 concerning the dangers of hydraulic fluid.

Removal
1 Unscrew the filler cap from the master cylinder fluid reservoir and drain off the fluid.

2 Prise the reservoir from the master cylinder and remove the seals.

3 Unscrew the union nuts securing the rigid brake lines to the master cylinder and pull out the lines. Cap the pipe ends to prevent loss of fluid.

4 Unscrew the mounting nuts and withdraw the master cylinder from the bulkhead or servo unit, as applicable. Remove the gasket on non-servo models.

Overhaul
5 Clean the exterior of the master cylinder. It is not possible to overhaul the master cylinder fitted to non-servo models, therefore if it is known to be leaking or damaged the complete master cylinder must be renewed.

On servo models proceed as follows.

6 Using circlip pliers, extract the circlip from the mouth of the cylinder.

7 Remove the primary and secondary piston components noting their locations. If necessary tap the cylinder on a block of wood.

8 Clean all the components in methylated spirit. Check the surfaces of the cylinder bore and pistons for scoring and corrosion, and if evident renew the complete master cylinder. If the components are in good condition remove and discard the seals and obtain a repair kit which will contain all the necessary renewable components.

9 Dip the new seals in fresh brake fluid and fit them to the pistons using the fingers only to manipulate them.

10 Reassemble the master cylinder in reverse order to dismantling and make sure that the circlip is fully engaged with the groove in the mouth of the cylinder.

11 On non-servo models check that the brake pedal pushrod protrudes from the bulkhead by between 9.0 and 9.6 mm. If not, loosen the locknuts and adjust the position of the stop light switch inside the car on the pedal bracket.

Refitting
12 Refitting is a reversal of removal, but fit a new gasket on non-servo models. Finally bleed the complete hydraulic system, as described in Section 2.