Note: Brake fluid is poisonous. Rinse the affected parts with copious amounts of cold running water and seek immediate medical attention if the fluid enters the mouth or eyes. Some types of brake fluid are flammable and can ignite if they come into contact with hot components. Take appropriate fire safety measures. Brake fluid is aggressive to paint and plastics - if it comes into contact with such surfaces, immediately wash off the fluid with plenty of water. In addition, the liquid is hygroscopic (absorbs moisture from the air) - old fluid may be contaminated with water and unusable. When topping up or replacing fluid in the system, use the recommended type of fluid from a freshly opened sealed container.
General description
1. Proper functioning of the brake hydraulic system is possible only if its components are free of air. Bleed the system to remove air.
2. During the bleeding procedure, add only clean, fresh brake fluid specified in Specifications type. Never reuse liquid. Make sure you have enough fluid before starting work.
3. If there is any doubt about the type of fluid filled into the system, flush the system with clean fluid and replace all seals.
4. If the brake fluid level in the master cylinder has dropped, find and repair the cause of the leak before proceeding.
5. Park your car on level ground (not slanted), turn off the ignition and select 1st gear or reverse. Block the wheels and release the handbrake.
6. Make sure all tubing and hoses are securely attached, couplers are tight, and bleeders are closed. Remove the dust caps and clean the dirt from the fittings.
7. Unscrew the cap of the reservoir of the brake hydraulic system and bring the fluid level to the line «MAX». Screw on the cap and be sure to keep the fluid level above the line «MIN» throughout the procedure, otherwise air will again enter the system.
8. There are a number of one-man brake bleeders available on the market. It is recommended to use one of these kits, as they greatly simplify the work and also reduce the risk of air and fluid escaping from the system being drawn back into the system. If such a device is not available, use the basic bleeding method (for two people), detailed below.
9. If a fixture is used. Prepare the vehicle as described above and follow the kit manufacturer's instructions. The procedure may vary slightly depending on the type of device used, its main course is also described below.
10. Whichever method is used, follow the correct bleeding sequence.
Pumping sequence
11. If components of only one of the circuits have been disconnected or removed (e.g. caliper or brake master cylinder) and while measures have been taken to minimize fluid loss, only this brake assembly needs to be pumped.
12. If the entire system is to be bled, proceed in the following sequence:
- a) Right front brake.
- b) Left rear brake.
- c) Left front brake.
- d) Right rear brake.
13. On all vehicles equipped with pressure sensitive brake pressure control valves (those. except Pickup models), bleeding the rear brakes may require more time due to the limitation of the working section of the system by the valves.
Pumping - the main method (for two people)
14. Prepare a clean glass reservoir and a suitable length of plastic or rubber tubing that fits snugly on the bleeder port. You will need the help of a second person.
15. If not already done, remove the dust cap from the bleeder fitting and fit a tube prepared for bleeding onto the bleeder. Immerse the other end of the plastic tube in the brake fluid previously poured into the reservoir.
16. Make sure the master cylinder reservoir is filled and keep the fluid level in it above the line «MIN» throughout the entire procedure.
17. Have an assistant press the brake pedal all the way down several times (to release the vacuum), and then keep it pressed.
18. While the pedal is depressed, loosen the bleed screw approximately one turn. When fluid stops flowing out of the fitting, clamp it and ask an assistant to slowly release the pedal. Check the fluid level in the reservoir again.
19. Repeat this procedure (paragraphs 17 and 18), until the escaping brake fluid is free of air bubbles. If the entire system is being bled, take breaks of at least five seconds between cycles on the first brake assembly so that the fluid has time to fill the channels of the master cylinder (see also paragraph 24 Chapters 11).
20. Clamp the bleeder screw, remove the plastic tube and install the dust cap. Do not overtighten the fitting.
21. Repeat the procedure on the remaining brake units in the above sequence.
Bleeding with non-return valve tool
22. These devices are a tube with a non-return valve that prevents air and fluid that have left it from being drawn back into the system. Some kits also include a transparent container (see photo).
23. Put the tube on the bleeder valve and open it. Apply the brake pad slowly and smoothly, then release it slowly. Repeat this action until the fluid coming out of the fitting is free of air bubbles.
24. These kits make the job so easy that it's easy to forget about emptying the master cylinder reservoir. Periodically check the fluid level in the reservoir and keep it at least above the line «MIN».
Pumping under pressure
25. These devices are powered by compressed air contained in the spare wheel chamber. However, note that the air pressure must be reduced (see the instructions supplied with the tool).
26. Attach the container filled with brake fluid to the master cylinder supply reservoir and to the spare wheel. Perform pumping by opening the fittings one by one (in the specified sequence) and draining the liquid until it is free of air bubbles.
27. This method has advantages because a large amount of liquid in the installed reservoir prevents air from entering the main cylinder during pumping. On all vehicles. fitted with pressure sensitive brake pressure control valves (those. except Pickup models), the pressure in the spare tire chamber should be as low as possible (however still valid for pumping), otherwise the valves may work, making it difficult to bleed the rear brake assemblies.
28. Pumping under pressure is especially effective when pumping «problematic» systems (airlock is stuck in a place where it is difficult to expel it) or when completely bleeding the system during the next fluid change.
All Methods
29. When priming is complete, rinse off spilled fluid, clamp bleeder fittings and install their dust caps.
30. Check and top up the fluid level in the nutrient tank (see section 1).
31. Pour out the brake fluid that came out during pumping - it is not suitable for reuse.
32. Check up elasticity of a brake pedal. If dips are felt during its movement, there is still air in the system and further pumping is required. If re-priming is not satisfactory, the master cylinder seals may be worn.