1. Check all brake line fittings for tightness. Look for worn hoses and for cracks or cuts.
2. If you are in doubt about the brake caliper or wheel cylinder, you should inspect them for signs of fluid leakage.
3. Prepare a clean container, a piece of rubber tube that fits snugly on the drain valve, and brake fluid.
4. Bleed the master cylinder first (see Bleeding air from master cylinder).
5. Loosen the nut where the hydraulic line connects to the master cylinder.
6. Have an assistant slowly press the brake pedal to the floor, which will force the air in the master cylinder to escape through the loose connection.
7. With the pedal fully depressed, tighten the connection. Release the pedal. The pedal must not be released until you tighten the connection, because. Otherwise, air may enter the cylinder.
8. Repeat this procedure until no more air comes out of the cylinder.
9. Bleed hydraulic systems separately, starting with the longest line (rear).
10. To bleed the brake system, clean the surfaces near the drain valves. Remove the rubber cap from the drain valve and put a piece of rubber tube on the nipple.
11. Lower the other end of the tube into a vessel in which so much brake fluid should be poured so that the end of the tube remains immersed in it during pumping.
12. Open the drain valve approximately 3/4 turn and have an assistant slowly sink the brake pedal to the floor and hold it in this position.
13. Close the drain valve and release the pedal.
14. Continue this operation until no more air bubbles come out.
15. When pumping the system, periodically check the fluid level in the reservoir. It must be filled to the top, otherwise air will enter the system again. Do not add fluid that has already been pumped out of the system into the reservoir.
16. Repeat the entire procedure for the second rear wheel.
17. Bleeding the front brake system is carried out in a similar way.
18. Fill the master cylinder with liquid so that its level in the reservoir is approximately 6-7 mm below the top edge.
19. Check the operation of the brake fluid level indicator by pressing on the black rubber bulb at the top of the reservoir (with the ignition on). The light on the dashboard should light up.
20. Check the feel on the brake pedal: it should be firm and not give a feeling of failure («viscosity»), which is a sign of the presence of air in the hydraulic actuator.