Mechanics

Clutch Master Cylinder

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How to Replace a Clutch Master Cylinder

The clutch master cylinder is a unit that is designed to operate the clutch secondary-slave cylinder to disengage the transmission from the engine when the vehicle is stopped or when shifting gears. The clutch master cylinder is a hydraulic unit that applies pressure to the slave cylinder when the clutch pedal is depressed. The clutch master cylinder is a reliable unit, but they can go bad. Common symptoms can include difficulty shifting, gear grinding, and not being able to shift the transmission into gear when the vehicle is stopped. 

Note: The clutch fluid should be flushed when replacing the clutch master cylinder. Make sure to allow the system to drain fully before refilling the new parts with fluid. Caution: Clutch fluid is brake fluid and 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.

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

1. Line wrench set

2. Pliers

3. Clutch/Brake fluid

4. Wrench set

5. Shop towels

6. Socket and Ratchet Set
 

Directions

Step 1 - Locate and activate the hood release cable, then release the secondary latch and raise the hood, support with prop rod if needed.

Step 2 - Disconnect the negative cable side of battery.

Step 3 - Open the vehicle’s hood and locate the clutch master cylinder. Normally, it is located on the driver’s side firewall.

Step 4 - Next, locate the slave cylinder located on the transmission and open the bleeder valve (usually an 8mm bleeder) allowing the clutch fluid to drain into a pan. Remove the lid from the clutch master cylinder for quicker draining.

Step 5 - After the fluid has fully drained, tighten the bleeder valve.

Step 6 - From inside the vehicle, locate the push rod that attaches the master cylinder to the top of the clutch pedal. Most have a slip pin that is held in with a cotter pin or retaining clip. Remove the cotter pin or retaining clip, disconnecting the pedal and push rod.

Step 7 - Return to the clutch master cylinder under the hood. Using a line wrench, remove the hydraulic line between the clutch master cylinder and the slave cylinder.

Step 8 - Most clutch master cylinders are mounted to the firewall with two bolts. Remove the bolts and slide it out and away from the vehicle.

Step 9 - Once removed, clean and prepare the area for the new clutch master cylinder. Make sure to avoid getting contaminants into the hydraulic lines.

Step 10 - Slide the new clutch master cylinder into the firewall of the vehicle and bolt it in place.

Step 11 - Reattach the hydraulic line to the clutch master cylinder.

Step 12 - From inside the vehicle, reattach the push rod to the clutch pedal.

Step 13 - Once the clutch pedal is reconnected, return to the slave cylinder and open the bleeder valve.

Step 14 - Fill the new clutch master cylinder with fluid and continue filling it until the fluid begins to drip from the slave cylinder.

Step 15 - When the fluid begins to drip, tighten the bleeder. Make sure to have a drip pan collecting the fluid.

Step 16 - Have a helper push the clutch pedal to the floor while you open the bleeder. A combination of air and fluid will come out. Make sure that your helper doesn’t release the clutch until you have retightened the bleeder. Continue this process until all air is out of the system. (Note: Constantly monitor the fluid level in the clutch master cylinder. Do not allow it to get too low. When all air is out of the system, refill the clutch master cylinder, cap it off, and check for leaks.)
 

Replacing a clutch master cylinder is a simple job that can save you hundreds of dollars. However, this is a general description of the process and your vehicle may have specific requirements. 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

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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.


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Article first published (Updated 2013-08-16)