A clutch slave cylinder works just like a drum brake wheel cylinder, except a slave cylinder only pushes in one direction to disengage the clutch where a wheel cylinder pushes in two directions because it has to push two brake shoes. Over time, the lip on the rubber seal in the slave cylinder may wear out and allow hydraulic-brake-fluid to leak out of the cylinder. In some instances a slave cylinder can be rebuilt, depending on the condition of the cylinder body.
Park the vehicle on a level paved surface. Set the parking brake. Raise the front of the vehicle with a jack and support with jack stands.
Place a drain pan under the slave cylinder. Use a wrench to remove the hydraulic line from the slave cylinder. Catch any brake fluid that leaks out of the line in the drain pan. Use a ratchet and socket to remove the bolts that hold the slave cylinder onto the transmission. Remove the slave cylinder and push rod. Pull the push rod out of the dust cover on the end of the cylinder.
Remove the dust cover from the end of the slave cylinder. Thoroughly spray the slave cylinder with brake cleaner.
Use a pair of snap ring pliers to squeeze together the ends of the snap ring that rides in a groove in the end of the cylinder. Remove the snap ring. Remove the plunger, rubber seal and spring. Note that the concave end of the plunger faces out. The end of the push rod fits in it.
Clean the inside of the cylinder with brake cleaner and allow to dry. Inspect the inside of the cylinder. If it has excessive scoring or pitting you should buy a new slave cylinder because it probably won't seal properly.
Wet the inside of the cylinder with brake fluid. Lubricate the new seal with brake fluid. Insert the spring and seal into the cylinder. The flat side of the seal faces outwards. Insert the plunger into the cylinder. Push it in far enough so that you can install the snap ring into its groove. Install the new dust cover over the end of the cylinder and slide the push rod into the hole in the dust cover.
Mount the cylinder on the transmission while positioning the push rod against the throwout bearing arm. Install and tighten the bolts. Install and tighten the hydraulic line. Use a wrench to open the bleeder screw on the slave cylinder and attach a piece of clear plastic tubing to the bleeder screw. Place the other end of the tubing in a clear container with a couple of inches of clean brake fluid in it.
Fill the clutch master cylinder with clean brake fluid and have an assistant press the clutch pedal four times. Keep the end of the tubing in the brake fluid in the container. As the pedal is pumped, you will see air exit the slave cylinder. After four pushes on the pedal, refill the master cylinder. Repeat until you don't see any air bubbles come out of the slave cylinder. Tighten the bleeder screw.
Raise the vehicle, remove the jack stands and lower the vehicle to the ground.
