Table of contents: Removal ↓ Installation ↓
The main brake cylinder is the main one in the brake system. It is non-separable, cannot be repaired and in case of malfunction is replaced as a set (see illustration 9.0).
Removal
1. Disconnect the bypass hose 1 supplying brake fluid from the reservoir to the clutch master cylinder and plug it with a suitable plug (see illustration).
9.1. Disconnect the bypass hose 1 supplying brake fluid from the reservoir to the clutch master cylinder and plug it with a suitable plug
2. Disconnect plug 2 of the brake fluid level in the reservoir (see illustration 9.1).
Drain as much brake fluid as possible from the reservoir. To do this, connect a hose with a container for collecting the fluid to the left front wheel brake bleed nipple, open the nipple and, "pumping" the brake pedal, drain the fluid. After draining, tighten the nipple.
3. Disconnect both brake lines 1 from the master cylinder and plug their openings with suitable plugs (see illustration).
9.3. Disconnect both brake lines from the master cylinder 1
4. Unscrew the 2 nuts securing the cylinder to the vacuum booster and carefully disconnect the cylinder from the booster (see illustration 9.3).
5. Remove the master brake cylinder together with the reservoir and, if necessary, separate them.
Installation
Installation of the master brake cylinder is performed in the reverse order of removal.
6. Install a new sealing ring between the brake booster and the brake master cylinder.
7. Fill the reservoir with new brake fluid, bleed the brake system and clutch hydraulics, see the relevant chapter.
[This publication is borrowed from the resource «AudiManual»]