Pressure-control relief valve (ABS models) - removal and refitting

Braking system / Pressure-control relief valve (ABS models) - removal and refitting

Removal
1 On ABS models, the pressure-control relief valves are located on the ABS hydraulic unit (see illustration).

19.1 Pressure-control relief valve locations on the ABS hydraulic unit

1 PCR valve, rear right brake circuit 2 Outlet, front left brake circuit 3 Inlet, from brake master cylinder secondary circuit 4 PCR valve, rear left brake circuit 5 Outlet, front right brake circuit 6 Inlet, from brake master cylinder primary circuit

2 Disconnect the battery negative (earth) lead (Chapter 5, Section 1).

3 Remove the air cleaner assembly as described in Chapter 4.

4 Remove the engine air inlet duct and air plenum chamber.

5 Disconnect the low fluid level warning multi-plug from the brake fluid reservoir.

6 Unscrew and remove the brake fluid reservoir filler cap, and completely seal the top of the reservoir using cling film or adhesive tape. This will reduce loss of fluid when the PCR valve is removed.

7 Unscrew the master cylinder mounting nuts, and carefully withdraw the cylinder from the servo unit, leaving the brake pipes still connected to it. Move the master cylinder over to the left-hand side of the engine compartment, to rest against the left-hand suspension turret. (Throughout this manual, left- and right-hand are as seen from the driver’s seat.)
8 Unscrew the servo unit mounting nuts, and move the unit to one side.

9 Position some rags beneath the ABS unit, to catch spilled fluid.

10 Clean around the valve to be removed.

Hold the PCR valve stationary with one spanner, and unscrew the hydraulic pipe union nut with another spanner. Pull out the pipe, and bend it slightly away from the valve.

11 Unscrew the PCR valve from the ABS unit.

Refitting
12 Refitting is a reversal of the removal procedure. On completion, bleed the hydraulic system as described in Section 15.