Removal and installation of the main brake cylinder (GTZ)

Note: A failed GTZ must be replaced. Manufacturers do not recommend attempting to rebuild the brake master cylinder.

1. The master brake cylinder is located in a niche under the windshield, fixed to the vacuum brake booster assembly and covered with a cover (see resist. illustration).



2. Remove the protective cover and, if necessary, remove the rubber seal of the engine compartment bulkhead to the required length (see illustration 12.1).

3. Remove the cap of the brake fluid reservoir and pump out as much fluid as possible (use a syringe or rubber bulb).

4. Put a rag under the fittings and prepare plugs to plug the open ends of the brake lines in order to prevent dirt from entering the system.

Attention: Brake fluid is one of the aggressive chemical compounds and, in contact with body panels, destroys the paintwork. Before proceeding with the procedure, cover the wings and front panel of the car with special covers, or just old blankets.

5. Disconnect the wiring connector of the brake fluid level sensor-switch from the GTZ tank (see resist. illustration). On models with a manual transmission, disconnect the hydraulic clutch pipe from the GTZ reservoir.




6. Remove the guide from the bulkhead of the engine compartment and loosen the union nuts securing the brake lines to the GTZ (see illustration 12.5). To avoid rounding of the splines of the nuts, use a special box wrench with a split head to loosen them. Slightly pulling outward, separate the brake lines from the master cylinder fittings.

7. Loosen the 2 fixing nuts and remove the master cylinder along with the reservoir and sensor-switch from the vacuum brake booster assembly - try not to spill the hydraulic fluid filling the cylinder onto the painted body panels. If necessary, disconnect the tank from the GTZ.

8. The GTZ is installed in the reverse order of its removal. Do not forget to replace the removed gaskets.

9. After installation, fill the cylinder and reservoir with brake fluid and bleed the system (see Section 3). Bring the fluid level up to the mark «MAX» (see chapter 1) and tighten the reservoir cap tightly.

10. Before starting the operation of the car, make sure that the brake system is functioning properly.