Power Brake Unit: Removal
- Siphon brake fluid from master cylinder reservoir. On all models except 320i, remove left portion of lower dash panel. On all models, remove operating rod clevis pin from brake pedal arm. Disconnect and plug hydraulic lines at master cylinder, including clutch hose.
- Disconnect vacuum hose from power brake unit (hydraulic lines on 733i). Remove power brake unit mounting bolts. On 320i only, separate master cylinder support from inner fender panel. Remove power unit/master cylinder assembly from vehicle. Separate master cylinder from power brake unit.
NOTE:
On 533i, 633CSi and 733i models, power steering pump also supplies hydraulic pressure through hydraulic accumulator to the power brake unit. If power steering fails, there will be sufficient pressure in the hydraulic accumulator to provide a few brake applications with full power.