If your vehicle's clutch master cylinder fails, you should conduct a clutch master cylinder replacement or repair. Luckily, this isn't as hard as it sounds, but you should do it as soon as possible to keep your vehicle driving safely and smoothly. Here's what you need to know to repair, replace, or bleed a clutch master cylinder.
What Is a Clutch Master Cylinder?
The clutch master cylinder is found in cars with a manual transmission and is similar to the brake master cylinder in its function. If you have an automatic car, you don't need to worry about clutch master cylinders.
The clutch master cylinder is connected to the clutch pedal and operates by generating hydraulic pressure, creating hydraulics for the clutch. If it is not working properly, your gears may grind, and in extreme cases, the transmission may even pop out of gear.
Where Is the Clutch Master Cylinder Located?
The clutch master cylinder is usually located inside the engine area of your vehicle, under your engine hood. The master cylinder is the smaller of the two cylinders connected to the car's firewall, right in front of the steering column.
Before doing anything with the clutch master cylinder, consult your owner's manual and make sure you're working on the correct portion of your engine. Incorrectly identifying the clutch master cylinder can have disastrous results. If you can't identify the clutch master cylinder yourself, you're better off taking your car to an auto shop to be repaired by a professional.
Clutch Master Cylinder Replacement Cost
The clutch master cylinder is generally not that expensive. It can range anywhere from $200 to $500 depending on your vehicle make and model. Don't just buy any old clutch master cylinder you can find, focusing only on the price tag. Make sure it's the correct one for your car.
Generally speaking, labor for a clutch master cylinder replacement or repairs can range from $150 to $300. Making the fix yourself can allow you to save this money, and often time, too, as a shop may need to keep your car overnight.
If you don't know much about car repair and maintenance, however, you may want to let the professionals handle the clutch master cylinder repair, since spending a little money upfront could save you from bigger issues and frustrations down the line.
Clutch Master Cylinder Repair Kit
If you're worried about having all the supplies necessary to do clutch master cylinder repairs on your own, fret not. For starters, most of the supplies you need are pretty basic and you'll have them lying around your home if you have even basic tools.
You can, however, invest in a clutch master cylinder repair kit. These can cost anywhere from $25 to $40 and can be purchased at an auto shop as well as online or from a local mechanic.
You could also borrow tools from a friend or neighbor if need be, since the materials for this project are pretty basic ones that most people will have. None of the materials are expensive or rare enough to warrant renting them.
When to Repair and Replace
There are a few signs that something is wrong with your clutch master cylinder. If you have any of these signs, move on to the following steps to repair your clutch master cylinder.
Most of these signs are pretty obvious, but a few are more subtle. By paying close attention to the feel and sounds of your vehicle, you will be able to spot them.
One sign that there's an issue with the clutch master cylinder is a soft pedal, meaning a pedal that has less resistance when you press down on it. There could be a variety of causes for this, including a clutch master cylinder that needs repairs.
Similarly, if it's hard to shift your car from one gear to another, there may be an issue with the clutch master cylinder. This can be dangerous as well if you're driving and find yourself unable to shift gears properly.
If your pedal is stuck to the floor or slow to rise, the clutch master cylinder could also be faulty.
If your clutch is really loud when shifting from one gear to another, it could also be an issue with the clutch master cylinder. It could be leaking, causing the noise.
Fluid issues could also be a sign of a problematic clutch master cylinder. If the fluid levels get low quickly, you may have a lead in the clutch master cylinder that needs to be repaired.
Removing the Clutch Master Cylinder for Repair
To repair the clutch master cylinder, it will first have to be removed. Make sure you do so carefully and do not damage the cylinder. Start by turning off your vehicle and giving it enough time to cool down completely.
Before you even start on the master cylinder itself, jack up the vehicle and place it on jack stands. This will make it easier to see where everything is.
Once the car is on jack stands, raise the hood of your vehicle. You can then remove the reservoir cap for the fluid container and drain the brake fluid to the minimum level. Place fluids in a container or a drip pan.
You will find the clutch pipeline connected to the master cylinder body. This will need to be removed using a line wrench. Turn the wrench counterclockwise to remove it. There are usually two screws that will need to be removed but some cars vary. You can apply penetrating spray to make it easier to remove the screws and use a socket to remove these nuts and take out the clutch master cylinder.
Once you remove the screws, pull the pipe line out. Be careful during this process to not drip fluids on other parts of your car or drop anything. Set any screws you removed safely to the side somewhere where they will not be lost, misplaced, or misshapen. You may want to place them in a plastic baggie and label them as you work on the clutch master cylinder.
Repairing the Clutch Master Cylinder
There's a thin woven lining between the master cylinder and the firewall. At the end of the master cylinder that's located close to the firewall, you will need to find the clip that operates the whole master cylinder. Use a screwdriver to remove it.
Once the clip is removed, the piston on the inside of the master cylinder will be removed. A spring, cap, and circular plastic should still be inside the master cylinder. Shake the master cylinder until this falls out. Clean the inside of the master cylinder using brake fluid and wipe it with cotton. This is the only thing that needs to be used to clean it.
Once it's cleaned, put fresh brake fluid on it. You will also want to soak the new parts with fresh fluids. Your repair kit should come with a new spring, cap, plastic lining, and piston. Soak all of these.
Place the cap on the flat end of the spring and place it in the body of the master cylinder. Attach the piston plastic ring and set the piston in the master cylinder. You can now place the clip back by pushing the piston with your screwdriver and inserting the round clip.
By following these steps, you've completed the repair process for your clutch master cylinder. Now it's time to place it back in your vehicle.
Replacing the Clutch Master Cylinder
Now that you've repaired your clutch master cylinder, it is time to reinstall it. Place the thin woven lining back that was removed earlier. Reattach the clip to the master cylinder pushrod and put the master cylinder back on the firewall of the engine.
Take your socket extension and tighten the two nuts securing the master cylinder back to the firewall. Make sure you are using the correct size socket, socket extensions, and ratchet. The clutch line can now be reconnected.
Tighten the connector screw in the middle of the master cylinder and clutch pipe line using the line wrench. Reconnect the fluid line and pour fresh brake fluid into the fluid reservoir. If you need to bleed the clutch, you may do that now that you have repaired and replaced the clutch master cylinder.
How to Bleed the Clutch Master Cylinder
If your car's clutch is not releasing correctly, the clutch master cylinder needs to have the air bled out of it. To start, find the clutch slave cylinder. The clutch slave cylinder is usually below and to the right-hand side of the master cylinder. On the bleeder valve, which you will need to use to bleed the system, there should be a small bolt. The purpose of this bolt is to discharge air pressure buildup.
To bleed the system you will need someone to assist you. The good news is this project is relatively short so it shouldn't be a huge time commitment for you or your assistant.
Have whoever is helping you step down on the clutch pedal from the inside of the vehicle. They should hold it down all the way to the floor. While they're doing so inside the vehicle, you should use a wrench to loosen the bleeder valve until hydraulic fluid comes out.
Make sure you have some type of container to catch the fluid. Don't let it drip onto other areas of the car. If you don't see fluid coming out right away, don't be alarmed. A bubble of air will actually come out before any fluid starts to appear.
Once everything has come out, tighten the screws on the bleeder valve. Your helper in the car should slowly release pressure on the clutch pedal. Make sure they do this very slowly until the pedal is at its normal rest position where you would find it when the car is off.
You can now check the master cylinder. Make sure it has enough fluid. If when you check it, it drains and air enters the clutch slave cylinder or clutch hose, you will need to start the process over and bleed the system at least once more, if not a few more times.
While you are bleeding the system, check for leakage from the cylinders or the clutch hose. If you find any leaks, you will need to make some replacements.
Once you've bled the system a few times, you can tighten the bleeder valve. Your friend inside the car can let off the clutch. You can then open up the top of the master cylinder to add hydraulic brake fluid till it is topped up. Make sure you do not overfill the clutch master cylinder.
Once you have finished any repairs you have taken on, it's time to test the car to make sure all of your hard work was not in vain. Before doing so, put away all of the tools you used on the project and wipe away any brake fluid on your car. Not doing so right away can damage the surface of your vehicle.
You should now take your car off the jacks.
It's now time to start your vehicle. Turn it on and use the clutch to engage the forward gears. While you do, pay special attention to your pedal. It should feel firm and the gears should change smoothly without any grinding or slipping as you change them. Test the reverse gear as well to make sure everything is engaging correctly.
While fixing a clutch master cylinder is certainly something you could bring your car into the shop for, if you have some car repair knowledge, you may want to do the project yourself.
Make sure you're also doing proper maintenance to your car regularly to prevent issues from arising. Many costly car problems can be avoided if you take a little time to do basic repairs and maintenance.