Brake Booster/Brake Master Cylinder, Overview

Brake booster/brake master cylinder, removing and installing

Note:
- Brake master cylinders and brake boosters from different manufacturers are used. Complete master cylinders and brake boosters can be replaced independently of each other
- Brake master cylinders can no longer be disassembled, i.e. servicing is not possible.
- Use only new brake fluid. Observe in formation on brake fluid reservoir!
- Brake line connection.

1. T 45 torx socket head bolt
- 25 Nm (18 ft. lbs.)
2. Self-locking nut
- 49 Nm (36 ft. lbs.)
3. Master cylinder
- 23.81 mm (0.93 inch)
- Cannot be repaired. If inoperative replace complete.
- Removing and installing. Brake Booster, Removing and Installing
4. Brake line
- Master brake cylinder/secondary piston circuit to hydraulic unit
5. Brake line
- Brake master cylinder/primary piston circuit to hydraulic unit
6. Sealing ring
- Always replace
7. Brake booster
- Adjust ball plunger refer to Fig. 1
- On gas engines vacuum source is from intake manifold.
- On Diesel engines vacuum source is from vacuum pump.
- Functional check
- With engine switched off, press brake pedal firmly several times (to exhaust booster vacuum).
- Now press brake pedal with normal foot pressure, hold pressure and start engine. If booster is working properly, pedal will give slightly under foot (booster assist becomes effective).
- If inoperative replace.
- One way valve -9- (in vacuum hose)
- Removing and installing
8. Seal
9. Vacuum hose
- Insert into brake booster
10. Brake fluid reservoir
11. Cap
12. Sealing plug
13. Supply hose
- From brake fluid reservoir to clutch master cylinder
14. Bulkhead





Fig. 1 Adjusting ball plunger
A = 158.5 mm ± 0.5 mm (6.2 ± 0.02)

Notes:
- Ball plunger must be set at right angles to brake booster surface when measuring
- Measure to end of ball plunger without gasket.