Overhaul

Dismantling

NOTE: The use of a small screwdriver with a rounded polished end is recommended to assist in the removal of the seals. Before proceeding, be sure that the master cylinder, work area, tools and hands are clean.

- To remove the fluid reservoir withdraw the roll pin, and carefully pull the reservoir off the master cylinder.
- Carefully lever out the reservoir seals, from the master cylinder body.
- Remove the end cap/retainer, taking care not to damage the mounting flange face.

NOTE: The secondary return spring loads the piston assemblies against the end cap/retainer.

Brake Master Cylinder:

- Withdraw the primary piston assembly from the bore of the master cylinder, and discard. Gently tap the cylinder on a soft or wooden surface, to remove the secondary piston. It may be necessary to lubricate the cylinder bore with new unused Castrol Girling Brake Fluid, to ease removal. In very difficult cases, carefully feed compressed air into the master cylinder front delivery port. Remove the spring, seal retainer, recuperating seal and washer, from the front end of the secondary piston. Taking care not to damage the piston, remove the remaining seal from the rear of the secondary piston. Discard all the old seals and associated items which will be replaced by those contained within the service kit.
- The service kit also contains a new primary piston assembly, and the old one should be discarded.

Inspection
- Examine the secondary piston and the bore of the master cylinder for visible signs of scoring, ridges and corrosion. If any doubt exists as to the condition of any component, then it must be renewed, or a replacement master cylinder fitted.

Assembly
- The components to be re-used should be cleaned in unused Castrol-Girling Brake fluid and placed on a sheet of clean paper, ready for assembly.

CAUTION: To help prevent damage, it is essential that generous amounts of clean brake fluid are used at all stages of seal fitting.

- Carefully fit the rear seal in its groove in the secondary piston; be sure that the lip of the seal faces towards the primary piston.

NOTE: When fitting seals, only use thumb and finger pressure. Squeeze the seal between the finger and thumb, into a ellipse, then press the raised part of the seal over the flange, using the fingers of the other hand.

- Fit the washer, new recuperating seal, seal retainer and spring to the front end of the secondary piston. Be sure that the seals are correctly fitted - as shown Fig 1.

CAUTION: Adherence to the following instructions is vitally important. Failure to comply will result in damaged piston seals.

- Carefully secure the master cylinder in a vice and generously lubricate the piston seals, with new, clean brake fluid.
- Fit the secondary piston assembly to the cylinder until the recuperation seal is resting in the mouth of the cylinder bore.
- Ensuring that the seal is not trapped, slowly rotate and rock the piston assembly while GENTLY introducing the piston into the bore. Once the front (recuperation) seal has entered the bore of the cylinder, SLOWLY push home the piston in one continuous movement, to avoid possible damage to the seals.

NOTE: It is essential that generous amounts of unused Castrol-Girling Brake Fluid are used to lubricate the cylinder bore and piston seals, while the above operation is being carried out.

- Repeat the lubricating and fitting procedure exactly for the primary piston assembly.

CAUTION: The primary piston assembly is a factory assembled component and no attempt should be made to dismantle or adjust it.

- Position a new end cap/retainer over the end of the master cylinder, be sure that the tag is correctly positioned.

Brake Master End Cap:

- Crimp the end cap/retainer to secure it to the master cylinder.

CAUTION: Take care not to pierce the end cap while crimping it in position.

- Lubricate The new reservoir seals with unused Castrol-Girling Brake Fluid and fit to the inlet ports.
- To fit the fluid reservoir, lubricate the seals and press the fluid reservoir into position on the cylinder. Secure with the roll pin.
- Replace the rubber washer in the filler cap with a new one.
- Position the master cylinder, and connect the pipe unions, do not fully tighten.
- Position the master cylinder to the power booster.
- Secure with the two bolts and spring washers.
- Tighten the pipe unions.
- Fill the master cylinder fluid reservoir with fluid to the correct specification.
- Bleed brake system.