The clutch master cylinder is located near the clutch pedal motor outlet.

It is a very simple hydraulic cylinder that is connected to the clutch pedal of our vehicle and to the impeller of this pedal by a hose full of oil.

As a hydraulic clutch, the clutch master cylinder is a complex system, but it is often easy to find the cause of its failure.

What is clutch master cylinder (clutch pump) and how does it work ?

The clutch master cylinder, or called clutch pump (upper clutch cylinder) is the main type of hydraulic clutch operating system. This simple hydraulic principle is used to transmit the required force from the clutch pedal to the slave cylinder (lower clutch cylinder).

This part of the clutch system is connected on one side to the clutch pedal via a lever mechanism. The other end is connected via a hose to the slave cylinder, which moves the clutch.

When to change the clutch master cylinder ?

The clutch master cylinder is a component that allows us to manipulate the clutch pedal correctly, always with less effort than we would need if this part were not present in our vehicle.

Like other components of the clutch system, the clutch master cylinder can exhibit very characteristic faults. It is therefore very important to be aware of all of them.

Depending on the vehicle model, repairing the clutch master cylinder is usually quite simple, as well as inexpensive.

On some car models all that is required is to purchase a new clutch master cylinder assembly, unscrew the clutch line, then remove the component retaining bracket, replace the new clutch pump or clutch master cylinder buy from after market.

Here, KOMP explain when it is necessary to repair the clutch pump of our vehicle or when to do the clutch master cylinder replacement:

When the pedal is stuck

This first symptom occurs when the clutch pedal of our vehicle is depressed, the clutch pedal goes down, but does not return to its initial position. If this happens, we cannot change gears, so we will have to stop our car until we replace the clutch master cylinder with a new one.

Hardly any brake fluid

In the reservoir where the brake fluid is located, we can see some marks on the side that indicate the amount we have in the reservoir. If the brake fluid is below the mark, it is important to top it up. Depending on the vehicle model, one type of fluid or another will be necessary.

But why does the brake fluid diminish? Over time, the clutch master cylinder or clutch pump loses brake fluid due to a possible leak in the master or slave cylinder of the clutch system.

Gear shifting is too jerky

When the clutch master cylinder is damaged, but we can continue to drive, this may be due to the fact that gear change is too abrupt during driving. As a result, the clutch may start to slip. It is important to press the clutch pedal firmly and consciously, but not violently.

When the pedal is soft or spongy

If at any point in your driving you notice that the clutch pedal is lighter and easier to depress than before, this is another symptom that indicates that the clutch pedal should be replaced. This is because the clutch master cylinder has air in it, so the pedal starts to feel softer.

Brake fluid is dark

The last indicator that may alert us to check our vehicle's clutch pump is if the brake fluid we have replenished suddenly becomes very dark.

This may be because one of the internal seals in the clutch master cylinder is failing. Rubber debris from these internal seals can break down with use and contaminate the fluid, thus discolouring the contents of our car’s reservoir.

However, if the brake fluid has not been changed recently, it is necessary to consult the owner’s manual of your car to find out the recommended maintenance interval.

To avoid clutch master cylinder or clutch pump wear, at KOMP, we have a wide range of clutch master cylinder for various different types of cars and trucks on the market.

In addition, we have a Development Department that is constantly creating new brake parts for new models.