Contents: Removal 🠛 Installation 🠛
Removal
1. Remove the brake master cylinder reservoir filler cap and fluid level sensor (refer to Section Schedule of current maintenance).
2. Where the reservoir is mounted directly to the master cylinder, suck out the brake fluid using a syringe, pipette or hydrometer. If the master cylinder or reservoir is to be replaced, remove the reservoir by simply pulling it straight up.
3. Where the reservoir is mounted remotely from the master cylinder, unscrew the nuts securing its bracket to the bulkhead, then unhook the rubber strap securing the reservoir to the bracket. Turn the reservoir upside down and drain the brake fluid into a suitable container. Disconnect the connecting hoses from the reservoir and remove their ends from the master cylinder by pulling them toward you.
4. Wipe the area around the brake pipe unions on the wall of the master cylinder and place a rag under the unions to catch any fluid. Draw the location of the unions, then loosen the union nuts and carefully remove the pipes. Plug the ends of the pipes and the master cylinder ports to minimize the loss of brake fluid and prevent dirt from entering the system. Rinse off any spilled fluid with cold water.
5. Loosen and remove the nuts and washers securing the master cylinder to the booster unit. Remove the master cylinder from the engine compartment along with the sealing ring, which must be replaced.
6. It is not possible to rebuild the master cylinder because its internal components are not sold separately. If even one component is faulty, the entire master cylinder assembly must be replaced. The only components that can be replaced separately are the cylinder reservoir seals and the O-ring installed between the master cylinder and the booster.
Installation
1. Before installation, check the distance between the end of the push rod and the contact surface of the booster (refer to Section Checking, removing and installing the vacuum booster unit).
2. Make sure the contact surfaces are clean and dry, then install a new O-ring onto the rear of the master cylinder.
3. Carefully install the master cylinder onto the booster, making sure that the booster pushrod enters the cylinder centrally, screw on the mounting nuts and tighten them to the specified Specifications effort.
4. On non-ABS models, wipe the brake pipe unions and install them into the master cylinder ports at the locations noted during removal. Tighten the union nuts to the torque specified in Specifications. Install the master cylinder and fill it with fresh fluid, then check all connections for leaks.
5. On ABS models, install the master cylinder and fill it with fresh fluid, then check all couplings for leaks. Bleed the cylinder as described in Section Bleeding the brake hydraulic system. Wipe the brake pipe couplings and install them into the master cylinder ports. Tighten the coupling nuts, being careful not to overtighten them - use a torque wrench and a special adapter.
6. On all models, completely bleed the brake hydraulic system as described in Section Bleeding the brake hydraulic system.