Mechanics

Clutch Slave Cylinder Replacement

How to Replace a Clutch Slave-Secondary Cylinder

A clutch slave or secondary cylinder is a hydraulic device used to release the clutch; thus, it disengages the engine and transmission when a vehicle with a manual transmission is stopped and in gear and when the transmission is shifted. In general, when you depress the clutch pedal, pressure is applied to the slave/secondary cylinder. It reacts by extending a rod and pushing the throw-out bearing arm. As a result, the throw-out bearing applies pressure against the pressure plate fingers and releases the clutch disc pressure from the flywheel. A bad or weak clutch slave cylinder can leak, cause difficulty shifting into gear when the vehicle is stopped, or cause a grinding when shifting. 

Caution: Clutch/brake fluid is corrosive. Avoid getting it on the vehicle’s paint. If it is on the paint, quickly wipe it off with a clean soft cloth. Wash the area with soap and water and dry. The clutch slave cylinder plays an important role in the system. Without it, shifting would be impossible. Although these are general directions, most slave cylinders are very similar and all work based on the same principal. By doing the work yourself, not only will you have the satisfaction of a job well done, but also, you will save money on labor.

Park your car on level ground with the engine off and the emergency brake on. Always raise a car according to the manufacturers recommended instructions and secure with jack stands. Also we will be dealing with brake fluid so be sure to wear protective clothing, eyewear and gloves.

Tools and Supplies Needed to Complete this Job

1. Floor Jack

2. Jack Stands

3. Wrench Set

4. Fluid Catch Pan

5. Slave/Primary Replacement Cylinder

6. Brake Fluid

7. Shop towels

Instructions

Step 1 - Find and release the hood cable, the hood "pop" open, release secondary latch and secure with prop rod if needed.

Step 2 - Disconnect the negative cable of the battery.

Step 3 - Locate the slave cylinder and disconnect the hydraulic line. (Note: Make sure to have a drip pan under the slave cylinder to catch fluid.)

Step 4 - Most slave cylinders are mounted with two bolts. Remove the bolts and the slave cylinder will come off.

Step 5 - Clean the area and prepare it for the new part.

Step 6 - Some new slave cylinders come with a plastic band that holds the push rod in place. Do not remove the retainer.

Step 7 - Install the new slave cylinder and bolt it in place.

Step 8 - Open the bleeder valve (usually 8mm) on the slave cylinder.

Step 9 - Fill the clutch master cylinder with clutch fluid. (DOT 3 or DOT 4 brake fluid) To confirm the fluid type needed, refer to the vehicle owner’s manual.

Step 10 - Allow the slave cylinder to fill with fluid until there is a steady drip of fluid from the bleeder. Tighten the bleeder.

Step 11 - Have a helper get in the vehicle and slowly depress the clutch while you open the bleeder. Tell the helper not to release the clutch pedal until you have retightened the bleeder. (Note: The plastic strap holding the push rod will break when the pedal is depressed and the bleeder is closed)

Step 12 - Check the clutch master cylinder fluid level and refill as needed. Do not allow it to get empty, or you will have to start over again. Repeat step 11 until there is no air left in the system.

Step 13. - With the bleeder shut, have your helper depress the clutch pedal. The plastic strap that held the pushrod on place should break. (If equipped)

Step 14 - At this point, the job is basically done. Make sure the pushrod moves properly. If there is too little movement, repeat step 11.
 

Best Practices

  • Always make sure the line fitting and flange is free from debris or it could cause a brake fluid leak
  • Flush the system with brake fluid to ensure proper operation of the new slave cylinder
By: Joe Feliciani / AKA Jacobandnickolas. If further assistance is needed, our certified car repair technicians are ready to answer your car questions. Also, gain manufacturer specific instructions and information by clicking - Auto Repair Manual
 

Related Car Repair Information

AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


COMMENTS TO THIS ARTICLE


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.



Article first published (Updated 2013-08-16)