Power Brake Booster, Replacing, L.H.D
Power brake booster, replacing
Preparation
Disconnect the battery lead
See Battery, disconnecting Battery Disconnecting.
Removal
Preparations for removing the power brake booster
Switch off the ignition.
Remove the cross member
See Brake fluid reservoir, replacing, L.H.D Brake Fluid Reservoir, Replacing, L.H.D.
(On 5 cylinder engines). Remove the screws and nuts from the engine mounting. Lift out the cross member.
Remove the air cleaner (ACL) housing
See Brake pipe master cylinder / ABS unit, replacing, B5254T2 Brake Pipe Master Cylinder / ABS Unit, Replacing.
Remove the plastic cap and the cable holder
See Brake pipe master cylinder / ABS unit, replacing, B5254T2 Brake Pipe Master Cylinder / ABS Unit, Replacing.
Remove the integrated relay / fusebox
See Replacing the brake pipe between the hydraulic unit, front wheel and junction , B5254T2 Replacing the Brake Pipe Between the Hydraulic Unit, Front Wheel and Junction.
Preparations for removing the ABS unit
Clean the brake pipes terminals at the master cylinder and ABS unit.
Place paper under the master cylinder to avoid brake fluid spillage.
Remove all the brake pipes from the master cylinder and the ABS unit.
Plug the master cylinder socket for the brake pipes.
Remove the ABS unit and bracket from the side member
The unit is secured with three screws.
Note! Store the ABS unit in such a way that no dirt can get into the pipe couplings.
Preparations for removing the master cylinder
Note! On cars with 6-cylinder engines: Disconnect the connectors from the master cylinder.Mark up a connector.
Disconnect the connectors on the power brake booster.
Note! If the car has hydraulic clutch: Block the hose to the clutch cylinder. Use hose pliers.
Remove the master cylinder
Avoid brake fluid spillage when removing.
Note! Ensure that the gasket between the power brake booster and the master cylinder stays in place on the master cylinder.
Remove the soundproofing panel and the power brake booster
For the soundproofing panel, see Bushing, brake pedal, replacing, M56, L.H.D, M58, L.H.D Bushing, Brake Pedal, Replacing
For the power brake booster, see Power brake booster, replacing, R.H.D Power Brake Booster, Replacing, R.H.D.
Transfer the components to the new power brake booster
Transfer:
- the pedal position sensor. See: Pedal position sensor, replacing Service and Repair
- the check valve
- the terminal for the check valve.
Installation
Install the power brake booster
Install the push rod for the power brake booster and the retaining clip on the brake pedal
Tighten the power brake booster. Tighten to 25 Nm.
Install the soundproofing panel.
Install the master cylinder
Note! Check that the gasket is in place on the master cylinder.
Tighten the nuts. Tighten to 25 Nm.
Install the vacuum hose on the check valve for the power brake booster.
Install the connectors and vacuum hose
Install:
- the connectors on the master cylinder and the power brake booster
- the vacuum hose on the check valve.
Note! The vacuum hose must be behind the bracket for the ABS hydraulic modulator.
Note! There are 2 connectors for the master cylinder on cars with 6-cylinder engines. One is for the pressure switch and the other is for the power brake booster.
Install the ABS unit and the bracket
Install the bracket in the side member. Tighten to 10 Nm.
Install the brake pipes in the master cylinder and in the hydraulic modulator
Tighten to 17 Nm
Install the integrated relay / fusebox and the connector for the ABS unit
See Hydraulic unit, replacing Service and Repair.
Install the air cleaner (ACL) housing
See Brake pipe master cylinder / ABS unit, replacing, B5254T2 Brake Pipe Master Cylinder / ABS Unit, Replacing.
Install the cross member
See Brake fluid reservoir, replacing, L.H.D Brake Fluid Reservoir, Replacing, L.H.D.
Fill and bleed the brake system
See Brake system, bleeding (using bleeding unit) Brake System, Bleeding (Using Bleeding Unit).
Checking the power brake booster
Depress the brake pedal several times until it feels stiff.
Hold the pedal down. Start the engine. The pedal should travel and feel softer.
Release the brake. switch off the engine. Wait 1 minute. Then depress the pedal. The pedal should still feel soft but should become stiffer when it is depressed several times.
There should be no leakage between the vacuum hose and the terminal at the power brake booster.
There should not be any leakage between the master cylinder and the power brake booster.
Check that the stop lamp functions.
If the stop lamp switch has been modified or changed after installation of the master cylinder and power brake booster it must be readjusted. See Stop lamp switch, replacing Service and Repair.