The clutch is a vital component of a manual transmission system and comprises of various small parts. The clutch plate is attached to the input shaft of the gearbox by splines, and is about 5" in radius with friction material on both sides. A spring which fixes the plate on the engine flywheel, and consequently forces the gearbox input shaft to rotate along with the engine, is called the diaphragm. It is fixed to the engine flywheel.
While changing gears, the clutch plate and the engine rotate separately because of a disengagement mechanism which releases the diaphragm. A hydraulic system or cable is used to connect the clutch pedal to the disengagement mechanism. When the pedal is pushed down, it initiates the disengagement mechanism which makes the diaphragm let go of the clutch plate.
Hydraulic clutches are mostly self-adjusting. When the friction material on the clutch plate wears out, it is time to re-adjust your clutch. As the place of disengagement mechanism shifts, re-adjustment is necessary to compensate for the shift in position. In hydraulic mechanisms, hydraulic fluid is sent to the master cylinder from where it pushes back the disengagement mechanism. The master cylinder has a valve which controls the flow of hydraulic fluid through it. This valve opens up only when the pedal is completely raised. Hence, when you put a foot on the clutch pedal for a long time it cannot self-adjust, resulting in a problem.
In a cable-operated clutch there is no self-adjusting mechanism, and the throw-out bearing is under no pressure when you are changing gears. In this type, there is a possibility of the cable stretching or the clutch plate wearing out early, and hence any adjustment should be done manually, once every few months.
The driver operates the pedal while sitting inside the car. The pedal gives the driver control of the engine power flow while starting the car and shifting gears. When the clutch is engaged, power transfers from the engine to the transmission and finally to the drive wheels. On disengagement, power transfer is ceased which helps the engine to run in spite of no power being transferred to the drive wheels.
Reasons For Re-Adjustment
- Difficulty in shifting or changing gears, or gear clashes
- The clutch is worn out
- The pedal is not as sturdy as it was before, and feels different while operating
- To adjust the engagement point at a position where you want it
- Open the driver's door, and kneel down beside it. This will make it easier for you to see the areas beneath your dashboard.
- With your right hand, press the clutch pedal down and hold it in that position for a while.
- You will find an assembly which is just above the shaft where the pedal is suspended. Locate a hook-like structure on the assembly.
- Keep pressing the clutch down with your right hand and at the same time push the hook upwards, until you hear a clicking sound.
- Let go of the pedal and check the adjustments you just made. In case you are unhappy and want to return to the initial settings, simply lift the clutch as high as you can with your toe to reset it.
- Place your foot under the pedal.
- Use your foot to push the clutch upwards, in the direction of the steering wheel. Push it as high as possible.
- Release the clutch pedal and test it to see if you like where it shifts. Although this method is not as effective as the previous one, it works best for self-adjusting pedals.
While going about the process, it is important that you keep your car manual with you so that you know certain specifications about the clutch pertaining to your car model.