6 Common Bad Clutch Master Cylinder Symptoms

A clutch master cylinder is a component found on cars fitted with manual transmission. The clutch master cylinder serves as the pump for the hydraulically operated clutch system. The work of the clutch master cylinder is to push fluid via the system down to the clutch slave cylinder so that it may disengage the clutch when the clutch pedal is pressed. Since they are hydraulic in nature, clutch master cylinders are usually prone to problems with leaks that will mess with their capability to displace fluid. In case the clutch master cylinder has got issues, it will lead to problems with the clutch pedal and shifting gears. In most cases, a bad clutch master cylinder produces some signs that can notify the driver that a potential issue has taken place, and it should be serviced right away.

Bad Clutch Master Cylinder Symptoms

Almost all vehicles have a clutch master cylinder (CMC) that produces hydraulics for the clutch. So it is a hydraulics system that supplies pressure in the vehicle’s engine. CMC is connected to the clutch pedal (CP). When someone moves foot from Clutch Padel, a rod pushes the brake fluid into the CMC and allowing the wheels to rotate. So if there any problem with your CMC, you will face some unusual problems while shifting gears. Besides, you might find some other signs that indicate you need to check your clutch master cylinder. So how to identify if you are facing a bad clutch master cylinder issue? Here are some of those most obvious signs list:

Hard to shift

One of the major symptoms of a bad clutch master cylinder is when you experience difficulty in shifting. The cylinder is hydraulic in nature and is thus prone to internal leaks that can mess with its power to displace fluid properly. In case the master cylinder is not in a position to properly create pressure, it will not be able to disengage the clutch well the moment the pedal is pressed. This may cause the gears to grind during shifting. Also, it may lead to a transmission that pops out of gear.

Low clutch fluid

This is among the first signs of a bad clutch master cylinder. Whether the fluid is low or dirty in the tank, you should check the cylinder as it might be bad. The dirty fluid can result from the seals inside the master cylinder breaking down because of wear and old age and contaminating the fluid. Seals that are aging are as well increasingly prone to leaks as days go by. A low fluid may be a sign of a leak somewhere in the system.

Abnormal clutch pedal behavior

A bad cylinder may as well have an abnormal pedal pressure. When the cylinder develops some internal problems, it will directly affect the feel of the pedal. If the master cylinder is leaky, the pedal will feel spongy or mushy, and in more vigorous situations, it may cause a pedal to sink to the floor and remain there when pressed.

Soft pedal

The pedal can be said to be soft when you press your foot on it and feel its normal resistance not being there. This can be brought about by a leak in the slave or master cylinder. The issue may emanate from the seals.

Oil on the master cylinder

This is another method of determining if you have a bad cylinder. Take a look under the hood of your car and check the clutch master cylinder. In case the bottom of the cylinder is wet and oily, then there is a chance of leakage, which means a bad cylinder that needs replacement.

Noisy engagement

When you are at the light with the brake on and the vehicle in gear, you may hear a loud sound as you hold down the clutch pedal. This might be caused by a leaking master cylinder that won’t hold the release fork when the pedal is pressed down.

CMC Replacement Cost

If you notice any of these listed symptoms, take your vehicles to a professional mechanic without wasting time. The clutch pedal completely falls when the CMC stops working; as a result, the gear will be unable to shift. Then you need a replacement, but it is not so costly. It would cost around 100$-300$ depending on models and built quality.


I hope you have already gone over the list of six bad clutch master cylinder symptoms. Every part of your car is important with the inclusion of a clutch master cylinder. Delaying or not repairing a master cylinder can lead to various issues and affect how you drive your car. If you note one of the signs that we’ve discussed above, it’s better if you seek the services of a professional mechanic to tackle it right away.

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