W/ 25.4 mm (0.999) Piston Diameter

Brake master cylinder with 25.4 mm (0.999 inch) diameter piston and brake servo, component summary

Note:
- 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, Bosch 5.0 ABS system page. Refer to Anti-lock Brake System (ABS), Bosch 5.0. Bosch 5.3 system, refer to Anti-lock Brake System (ABS), Bosch 5.3.

1. Brake master cylinder
- Diameter: 25.4 mm (0.999 inch)
- Cannot be repaired. If malfunctioning, replace as complete unit only.
- Must be removed and installed together with the brake servo
- Removing and installing. Refer to Brake master cylinder with 25.4 mm (0.999 inch) diameter piston and brake servo, removing and installing as a unit.
2. T45 Torx(R)
- 25 Nm (18 ft. lbs.)
3. Flange nut
- Always replace
- 50 Nm (37 ft. lbs.)
4. Sealing plug
- Moisten with brake fluid and insert into brake master cylinder
- Press brake fluid reservoir into sealing plugs
5. Brake fluid reservoir with brake fluid level warning switch
Functional check:
- Remove brake fluid reservoir cap and with the ignition switched on push on strainer in reservoir.
- The warning light in the instrument panel insert comes on and an audible warning signal sounds.
- Removing and installing
- Fluid couplings are on the side of the reservoir
- Pay attention to information found on the label on the reservoir before adding fluid
6. Seal
7. Brake fluid reservoir cap
8. Fluid supply hose
- From brake fluid reservoir to clutch master cylinder
9. Seal
- Install in groove in brake master cylinder
- Replace after removing brake master cylinder
10. Brake servo
- Removing and installing
- Adjusting ball head refer to Fig. 1

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 unit is working properly, pedal will be felt to give slightly under foot (servo assistance becomes effective).

If malfunctioning:
- Replace as complete unit only.
11. Gasket
- Brake servo supplied with gasket glued on
- Replace only if damaged
12. Vacuum hose Install into brake servo On gasoline engines vacuum is supplied from intake manifold
13. Bulkhead
14. Brake line
- 15 Nm (11 ft. lbs.)
- Brake master cylinder/primary piston circuit to hydraulic control unit
15. Brake line
- 15 Nm (11 ft. lbs.)
- Brake master cylinder/secondary piston circuit to hydraulic control unit
16. Bolt
- Screw in as far as stop
- Attaches brake fluid reservoir





Fig. 1 Adjusting ball head
a = 159 mm ± 0.5 mm (6.26 inch ± 0.02 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.