Vacuum booster — removal and installation (BMW 3 Series E21)

Removal

Remove the brake fluid from the hydraulic reservoir using a syringe.

On the 323i model, remove the fuel injection system mixture regulator.

Remove the retaining clip and disconnect the brake booster pushrod from the brake pedal.

Disconnect the lines from the master cylinder and plug the holes in the lines and the master cylinder. Disconnect the hose from the booster.

Loosen the nuts securing the vacuum booster to the front shield bracket and to the bracket on the wing splash guard.

Remove the vacuum booster assembly from the master cylinder by pushing it forward.

Remove the protective cover, gasket, buffer washer and replace the vacuum booster air filter.

Installation

The vacuum booster is installed in the reverse order of removal. When attaching the booster pushrod to the brake pedal, ensure that the brake light switch button "A" protrudes by 5-6 mm.



After installing the vacuum booster, bleed the brake system to remove air from it.

Replacing the check valve

Removing the check valve is easy. Install the new valve with the arrow or black side facing the intake manifold. Replace the clamps each time you remove the check valve.