Car hydraulic clutch: what it is and how it works

The car clutch is a fundamental component that sometimes tends to be neglected and, above all, little known: for example, do you know what the hydraulic clutch is , and if it is present on your car?

Here’s everything there is to know.

The most common car clutch

Without the car clutch it would not be possible to start the vehicle itself, and furthermore gear changes would not take place safely: this component, located between the car engine and the gearbox, is connected to the passenger compartment by means of the special pedal, capable of operating it mechanically. or hydraulically.

Specifically, there are actually 3 types of clutch (based on the type of operation):

  • “wire” clutch– mechanically controlled by a cable
  • electromagnetic clutch– activated by an electromagnetic reaction
  • hydraulic clutch(the most common today) – works via a conduit that contains a special oil

To indicate in a simplified way how the clutch works we can say that its action is based on the approach and removal of some components necessary for the motion of the vehicle: to do this, it is essential that the fluids are always at the right level, especially in the case of hydraulic clutch.

The hydraulic clutch: how it works

The hydraulic clutch consists of a piston pump directly connected to the pedal, a reservoir for the fluid (usually the same as the brakes), a pipe and an actuator that acts on the lever itself.

Having the hydraulic clutch reduces the effort on the pedal and better isolates the passenger compartment from the vibrations coming from the engine, which is why this clutch is the most widespread of recent times, on cars with manual transmission.

The main maintenance mainly concerns the replacement of the hydraulic oil: this procedure must take place (as prescribed) every 3 years or 60,000 km. As always, meeting this deadline will protect you from some possible inconveniences, let’s find out which ones.

Problems with the hydraulic clutch

If it is true that the hydraulic clutch makes the clutches fluid, remember that it can still be subject to various malfunctions (like every clutch, for that matter).

For example, every time you press the pedal, it pushes the pump piston, exerts pressure on the hydraulic fluid from the tank and transmits it to the actuator cylinder: in this way you can easily change gear, but a leak may occur in the circuit, with unpleasant consequences.

If air enters, it will be necessary to vent the auto-hydraulic clutch : even in this case, since it is a complicated procedure, avoid doing it yourself and contact a professional.

Another inconvenience concerns any oil leaks : specifically, if you happen to find oil under the pedal (after putting a cloth to limit the damage) you will have to take the car to the workshop, because it will be a leak of the master cylinder, whose pump it is located just below the pedal board.

Another problem with the hydraulic clutch may concern the pedal, which remains lowered and not in the standard position: in this case, first of all put your foot under and force to pull it up. If you can, at this point you could reach the nearest mechanic who will (probably) tell you that the pump or control cylinder needs to be replaced.

The last most common problem on the hydraulic clutch is related to the very hard pedal: if it is not the fault of the stuck mat (it can happen) it is probably the thrust bearing or the pressure plate, and not the disc.

Now that you know everything about the hydraulic clutch , check now if it’s time to change the oil to take care of your car.


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