Note: Before starting work, refer to the warning at the beginning of Section 2 concerning the dangers of hydraulic fluid, and to the warning at the beginning of Section 5 concerning the dangers of asbestos dust.

Removal
1 Chock the front wheels then jack up the rear of the car and support it on axle stands (see “Jacking and vehicle support”). Remove the rear roadwheels and ensure that the handbrake is released.

2 Remove the hub/drum, as described in Section 11.

3 Note the location of the brake shoe upper return spring then unhook and remove it.

4 Pull the handbrake lever on the rear shoe fully forwards so that the upper ends of the shoes are clear of the wheel cylinder. Wedge the lever in this position using a block of wood.

5 To minimise fluid loss, unscrew the master cylinder reservoir filler cap and place a piece of polythene over the filler neck. Secure the polythene with an elastic band ensuring that an airtight seal is obtained. Alternatively, use a brake hose clamp, a G-clamp, or a similar tool with protected jaws, to clamp the flexible hydraulic hose supplying the rear brakes (see illustration).

10.5 To minimise fluid loss, fit a brake hose clamp to the flexible hose

6 Unscrew the hydraulic pipe union nut from the rear of the wheel cylinder.

7 Unscrew the two mounting bolts and withdraw the wheel cylinder from the backplate (see illustration). Take care not to spill any brake fluid on the brake shoe linings.

10.7 Rear wheel cylinder mounting bolts (arrowed)

8 Clean the exterior of the wheel cylinder.

Note that on all models with a diagonally split hydraulic circuit the rear wheel cylinders incorporate compensators which must not be dismantled.

Overhaul
9 Pull off the dust excluders (see illustration).

10.9 Exploded view of a rear wheel cylinder

1 Cap
2 Bleed screw
3 Dust excluder
4 Piston
5 Seal
6 Spring seat
7 Spring
8 Body

10 Extract the pistons, seals and return spring; keeping each component identified for location.

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

12 Clean the pistons and cylinder with methylated spirit or clean brake fluid then dip each component in fresh brake fluid and reassemble in reverse order; making sure that the lips of the seals face into the cylinder.

When completed, wipe clean the outer surfaces of the dust excluders.

Refitting
13 Clean the backplate and refit the wheel cylinder using a reversal of the removal procedure. Refer to Section 11 when refitting the hub/drum.

14 Make sure that the brake hose clamp or polythene sheeting is removed then bleed the hydraulic system, as described in Section 2.