Master Cylinder, Replacing

Master cylinder, replacing

Note! The illustrations in this service information are used for different model years and/or models. Some variation may occur. However, the essential information in the illustrations is always correct.

Preparatory work

Disconnect the battery lead. See: Battery, disconnecting Battery Disconnecting.

Caution! It is important that no contaminants enter the brake system.

Before starting work, clean around the brake fluid reservoir cap and the pipe couplings.
If necessary, also clean the hose connections and the connections between the reservoir and the master cylinder.

Caution! Relieve the check valve in the power brake booster; alternatively pump the brake pedal until it has no travel.This is so that no vacuum remains when the master cylinder is removed. Otherwise there is a risk that the O-ring will be sucked into the brake booster.

Hint: Position paper under the master cylinder to protect the paintwork.

Caution! Never, under any circumstances, open the master cylinder. Reassembling it requires special equipment and facilities.

Removal

Removing the torque rod
Remove the torque rod. See: Brake fluid reservoir, replacing Service and Repair.

Disconnecting the connectors




Disconnect the connectors at the brake fluid reservoir and at the power brake booster.
Block the hose to the clutch cylinder. (Applies only to cars with manual transmission).
Use hose pliers.

Removing the brake pipe





Remove:
- the brake pipes at the master cylinder
- the 2 upper brake pipes on the hydraulic modulator.
Plug the holes on the ABS hydraulic modulator so that that contaminants cannot get into it.

Removing the master cylinder





Remove:
- the 2 nuts
- the master cylinder from the power brake booster
- the hose from the brake fluid reservoir (applies to cars with hydraulic clutch).

Installation

Note! For tightening torques, see: Tightening torque Tightening Torque.

Installing the master cylinder




Transfer the brake fluid reservoir to the new master cylinder.
Check that there is no dirt in the terminals.
Lubricate the O-rings and any hoses with brake fluid or glycerin.

Note! Do not use a soap solution or mineral oil to lubricate the hoses. Use brake fluid or glycerin.

Install:
- the brake fluid reservoir from directly above -
- the screw on the underneath of the brake fluid reservoir. Tighten. See: Tightening torque Tightening Torque.

Installing the brake pipes




Install the brake pipes on the ABS hydraulic modulator and the master cylinder. Tighten. See: Tightening torque Tightening Torque.

Installing the connectors




Install the connectors on the brake fluid reservoir and the power brake booster.

Installing the torque rod
Install the torque rod. See: Brake fluid reservoir, replacing Service and Repair.

Finishing

Bleed the brake system. See: Brake system, bleeding (using bleeding unit) Brake System, Bleeding (Using Bleeding Unit).
Check the air in the brake system. Check for brake fluid leakage. See: Brake pipe master cylinder / ABS unit, replacing Brake Pipe Master Cylinder / ABS Unit, Replacing.
Connect the battery lead. See: Battery, disconnecting Battery Disconnecting.