Brake Fluid Pump: Service and Repair

NOTE:
- When changing the high-pressure pump/electric motor, it is advisable to remove the pressure accumulator before the hydraulic unit is removed from the car.
- Plug the connections on the pump body.

Removal
1. Remove the hydraulic unit.
2. Disconnect the pressure pipe from the pump body.
- Plug the pressure pipe's connection.
3. Unplug the connector from the terminal block by pressing the catch aside.
4. Remove the supply hose from the pump body.





5. Unscrew the high-pressure pump/electric motor's retaining bolt in the front mounting point.

Important: Note the order in which the damping sleeves and washer should be installed.

6. Unhook the high-pressure/electric motor from the rear mounting point.
7. Remove the pressure switch.
- Use special tool (16) 89 96 571.

NOTE: If the pressure switch is tightened down hard, a suitable counter stay can be placed between the pump body and the hydraulic unit.


Installation





1. Install a new 0-ring and screw in the pressure switch.
- Tighten to: 23 (17 ft lb)
2. Connect the supply hose to the pump body.
3. Install the high-pressure pump/electric motor to the rear mounting point.
4. Install the damping sleeves and washer.
- Tighten the high-pressure pump/electric motor's retaining bolt.
5. Plug the connector into the terminal block.
6. Connect the pressure pipe to the pump body.
- Install the pressure accumulator after installing the hydraulic unit in the car.
- Tighten to: 40 Nm (29.6 ft lb)
7. Fill up with brake fluid, DOT 4 specification.
8. Bleed the brake system.
9. Switch on the ignition and check that the brake and ABS warning lamps go out.
10. Drive the car on test and check that the brake and clutch systems are in perfect working order.