Wear protective goggles when bleeding the brake system. If liquid does get into your eyes, rinse immediately with water and seek medical attention. Most types of brake fluid are flammable and can ignite if they come into contact with, for example, hot engine parts. Therefore, brake fluid must be handled with as much care as gasoline. When topping up or changing brake fluid, always use the recommended type and take it from a container that has just been opened. Never reuse fluid left when the system was bled, and do not add fluid to the reservoir that has been open for a long time, because. it is potentially dangerous.
Brake fluid actively dissolves paint and plastic; if it spills, wash it off immediately with plenty of water.
Bleeding the hydraulic system is necessary in order to remove any air that may have entered it during the removal or installation of hoses, brake lines, caliper or master cylinder.
If air has entered the system due to a low brake fluid level, or as a result of the brake pipes being disconnected from the master cylinder, then all four brake mechanisms will probably need to be bled.
If the brake pipe was disconnected only at the wheel, then only the caliper or wheel cylinder is pumped.
If the brake pipe was disconnected in the connector located between the master cylinder and one of the brake mechanisms, then the part of the system that is serviced by the disconnected pipe should be bled.
When bleeding the entire system, bleed it in this order: right rear, left rear, right front, and finally the left front brake.
1. Remove the residual vacuum from the vacuum booster by depressing the brake pedal about 30 times with the engine off. This will also relieve pressure in the anti-lock brake system, where present.
2. Remove the master cylinder reservoir cap and fill the reservoir with brake fluid. Install the cover.
During the bleeding procedure, check the fluid level as often as possible and add fluid as needed to prevent the level from falling below the acceptable level when air bubbles can enter the master cylinder.
3. To carry out the bleeding procedure, you will need an assistant, an empty transparent plastic container and a piece of transparent plastic or vinyl tubing that can be placed on the bleed valves. You can also use a special pumping kit «without an assistant». This kit usually contains a tube or bottle with a built-in one-way valve - in this case, the pedal will depress normally, but when it is released, air will not enter the system back. When using the set «without an assistant» follow the instructions attached to it; the same for pressure bleed kits. In any case, you will also need a supply of fresh brake fluid of the recommended type and a wrench to work with the bleed valve.
4. Starting at the right rear wheel, loosen the bleed valve slightly, then tighten it until it is closed but can be opened quickly and easily.
5. Put one end of the tube on the bleed valve and immerse the other end in a container of brake fluid.
6. Have an assistant depress the brake pedal several times and then hold it firmly down.
If the vehicle is equipped with ABS, have an assistant depress the pedal at least 12 times.
7. With the brake pedal depressed, open the bleed valve just enough to allow a trickle of fluid to flow out of the caliper or wheel cylinder. Your assistant should gently depress the brake pedal to the end and keep it in this position. Watch the air bubbles escape through the submerged end of the tube. When the fluid flow slows down after a couple of seconds, close the valve and ask the assistant to release the pedal.
8. Repeat the steps in the previous two paragraphs until no more air bubbles come out of the tubes, then tighten the bleed valve and move on to the rear left wheel, then the front right, and finally the front left, in that order, repeating the same procedure. Remember to check the fluid level in the master cylinder reservoir frequently.
Never use old brake fluid. It contains moisture that damages brake components.
9. At the end of the entire procedure, fill the master cylinder with fluid.
10. Check up work of brake mechanisms. The depressed pedal should stand motionless, not sink. Repeat the entire process if necessary. Do not use the vehicle if you are not sure that its braking system is working properly.