Examination
1. To check, press the brake pedal several times to release the vacuum, and, holding the pedal down, start the engine. As soon as the engine starts, you should feel a clear movement of the pedal up as the vacuum builds up. Let the engine run for a couple of minutes and turn it off. If now when you press it you feel a "hard" pedal and further pressing makes it even harder, reducing its travel, the booster is working properly.
2. If the booster does not operate as described above, check the booster check valve as described in paragraph 13. On diesel engines, also check the operation of the vacuum pump as described in paragraph 20.
3. If the amplifier still does not work, then the fault is hidden inside it. Since the amplifier is disassemblable only in principle, spare parts are not supplied for it - the faulty amplifier is subject to replacement as a whole.
Removal
4. Remove the brake master cylinder as described in paragraph 10.
5. Carefully remove the vacuum hose tip from the booster, being careful not to damage the seal.
6. Loosen the mounting screws and remove the storage box from under the front panel on the driver's side.
7. Under the dash, locate the servo rod and note how it is connected to the brake pedal. On right-hand drive models, the rod is connected to a lever mounted to the left of the clutch pedal. On left-hand drive models, it is connected directly to the pedal. In both cases, the rod is hinged; to disconnect the rod from the pedal/lever, depress the hinge latches and lift the brake pedal to disconnect the rod hinge end.
8. Remove the Toex bolts securing the servo booster to the pedal bracket and engine shield.
9. Remove the amplifier from the engine compartment. Remove the gasket installed between the amplifier and the shield. Replace the damaged gasket.
Installation
10. Before installation, check the adjustment of the booster rod. After removing the gasket, check the size (fig. 12.10). If adjustment is required, the size can be changed by loosening the lock nut and rotating the rod. After completing the adjustment, tighten the lock nut.
11. Clean the mating surfaces of the amplifier and the shield, install the gasket, then the amplifier.
12. From the passenger compartment, check that the stem and pedal are properly connected by clicking the hinge into place. Lift the pedal by hand to ensure that the connection is secure.
13. Install the servo booster mounting bolts and tighten them to the specified torque.
14. Adjust the position of the brake light contact sensor as described in paragraph 17.
15. Install a storage box under the front panel.
16. Carefully insert the vacuum hose tip into the booster, being careful not to damage the seal.
17. Install the master cylinder as described in paragraph 10.
18. Bleed the hydraulic system as described in paragraph 2.
19. Bleed the brake hydraulic system as described in chapter 6.