W/ 23.81 mm (0.937) Piston Diameter

Brake master cylinder with 23.81 mm (0.937 inch) piston diameter and brake servo, component summary

Note:
- Brake master cylinders and brake servos can be replaced separately.
- Brake master cylinders can no longer be disassembled, i.e. there is no provision for servicing.
- Use only fresh brake fluid. Pay attention to information on the brake fluid reservoir.
- Brake line connections to master cylinder. Refer to Anti-lock Brake System (ABS), Bosch. Bosch 5.3 system, refer to Anti-lock Brake System (ABS).

1. T45 Torx(R)
- 25 Nm (18 ft. lbs.)
2. Self-locking nut
- 49 Nm (36 ft. lbs.)
3. Brake master cylinder
- Diameter: 23.81 mm (0.937 inch)
- Cannot be repaired. If malfunctioning, replace as complete unit only.
- Removing and installing. Refer to Brake master cylinder with 23.81 mm (0.937 inch) diameter piston, removing and installing.
4. Brake line
- 15 Nm (11 ft. lbs.)
- Brake master cylinder/secondary piston circuit to hydraulic control unit
5. Brake line
- 15 Nm (11 ft. lbs.)
- Brake master cylinder/primary piston circuit to hydraulic control unit
6. Seal
- Always replace
7. Brake servo
- On gasoline engines vacuum is supplied from the intake manifold
- On Diesel engines vacuum is supplied from the vacuum pump

Functional check:
- With engine switched off, depress brake pedal firmly several times (to deplete vacuum in brake servo).
- Depress and hold brake pedal with average foot pressure and start engine. If servo is working properly, pedal will be felt to give slightly under foot (servo assistance becomes effective).

If malfunctioning:
- Replace as complete unit only.
- Check valve in vacuum hose -9-
- Removing and installing. Refer to Brake servo for brake master cylinder with 23.81 mm (0.937 inch) diameter piston, removing and installing.
- Adjusting ball head refer to Fig. 1
8. Gasket
9. Vacuum hose
- Insert into brake servo
10. Brake fluid reservoir
11. Fluid reservoir cap
12. Sealing plugs
13. Supply hose
- Where applicable
- From brake fluid reservoir to clutch master cylinder
14. Bulkhead





Fig. 1 Adjusting ball head
Dimension -A- = 159 ± 0.5 mm (6.26 ± 0.020 inch)

Note:
- The ball head must be positioned at right angles to the mounting surface of the brake servo unit when measuring.
- Measure up to end of ball head with no gasket installed.