Hydraulic fluid is poisonous. It also dissolves paint well. Be careful not to allow liquid to come into contact with exposed areas of the body or eyes. Keep a rag handy to catch spilled liquid, and if it comes into contact with painted surfaces, immediately wash off the liquid with copious amounts of cold water.
Air in the hydraulic system may cause the clutch to not fully engage when the pedal is depressed. Air can enter the system during the removal of any of its components, and also if the fluid level in the master cylinder reservoir falls below the allowable level. Also, sometimes air enters the system through openings that are too small for the fluid to leak. In this case, the system needs a major overhaul.
To bleed the system, you will need an assistant to depress the clutch pedal, a clear plastic container, and a piece of flexible clear tubing the correct diameter for the bleed valve. You can also use the pumping kit without an assistant. It usually consists of a tube or bottle with a built-in one-way valve - in this case, when the pedal is released, air will not flow back into the system. If you use such a kit, follow the instructions that come with it. In both cases, you will need some fresh brake fluid of the recommended type and a special bleed valve wrench.
1. Check the liquid level in the reservoir. Top up if necessary to bring the level up to the mark «full» or «MAX». Use only the recommended type of fluid and do not mix different types of fluids. Never use liquid from a container that has been left uncovered for a long time, as it absorbed moisture from the air, making it unusable. During the pumping process, you will often have to check the fluid level in the tank. If it falls too low, air will enter the system.
2. Apply the parking brake. Jack up the front of the car and place it securely on axle stands.
3. Remove the cap from the bleed valve on the slave cylinder (see illustration).
4. Put the end of the plastic tube on the bleed valve fitting. Fill the container about one-third full with clean liquid, then dip the other end of the tube into it.
5. Slightly loosen the bleed valve, then tighten it until it is easy to release.
6. Ask an assistant to squeeze the clutch pedal several times and hold it in the fully depressed position.
7. With the pedal depressed, open the bleed valve about half a turn. When the liquid stops flowing through the tube into the container, tighten the valve. Depress the pedal again, and while holding it depressed, immediately release the valve. Do not release the pedal when the bleed valve is open.
8. Repeat this procedure until no more air bubbles pass through the tube. Remember to constantly check the fluid level in the reservoir.
9. Fully tighten the bleed valve, remove the tube and install the valve cap.
10. Check the fluid level in the reservoir again to make sure it reaches the top mark, then test drive the vehicle to check clutch operation.