Clutch is one of the essential devices in manual vehicles. It is installed between the engine and the transmission. It is a component that cuts off and transmits power between the engine and the vehicle transmission. It can be said that the state of the clutch directly affects the dynamic performance of the vehicle.

The clutch is mainly composed of clutch friction plate, clutch pressure plate and clutch release bearing, also known as "clutch three piece set". The clutch pressure plate is the most important part of the clutch assembly, which determines whether the clutch will tremble, be too heavy and be used for a long time after installation; The clutch friction plate determines the service life of the clutch and the effect of shock absorption and noise reduction; The clutch release bearing is an important part of the clutch release system, which determines the release efficiency of the clutch system and the wear rate of the pressure plate.

In case of any problem in any one of the three parts of the clutch, it is generally not replaced separately, but all the three parts are replaced together. The replacement cycle of the clutch three-piece set varies from vehicle to vehicle. If it is normal wear and tear, it can generally be used for about 100000 kilometers, but there are not a few vehicles that change the clutch after 50000 or 60000 kilometers, mainly because of improper use methods.

We can judge whether the clutch of our vehicle should be replaced by the following methods:

1. The vehicle lacks power, especially when climbing a slope;

2. When the vehicle needs to accelerate, the engine speed rises quickly, but the vehicle speed rises slowly;

3. When the vehicle is in gear 1, pull the handbrake or step on the brake to start, the vehicle will not stall;

4. When opening the engine compartment lid, you can smell obvious burnt smell, especially at the junction of engine and transmission.

When some car owners use the clutch, they find that there are always slippage, incomplete separation, shaking, abnormal noise and other phenomena. In this case, do they need to replace the clutch? In fact, some faults can be eliminated through independent maintenance. Vehicle owners can repair them by themselves according to the following methods.

1. Clutch slip

(1) Fault phenomenon:

When the vehicle starts in gear 1, it cannot start smoothly after releasing the clutch pedal.

When accelerating, the vehicle speed cannot be increased with the engine speed, so the driving is weak. In serious cases, it will produce burnt odor or smoke.

During the start-up test, the engine was supposed to shut down, but it didn't.

(2) Possible causes:

The free stroke of clutch pedal is too small or there is no free stroke.

The connection between clutch pressure plate and flywheel is loose and the pressing force is weakened.

The oil stain between the release bearing sleeve and the guide pipe is serious, and the release bearing cannot return.

The surface of the clutch plate is ablated, hardened or greasy, resulting in reduced clutch friction.

The working surface of clutch plate, pressure plate or flywheel is seriously worn.

The pressure spring is weak or broken, the diaphragm spring is weak or cracked, and the pressing force decreases.

(3) Maintenance steps:

① Check whether the free stroke of the clutch pedal is suitable. If it is not suitable, adjust it. Note that the hydraulic type is mostly self-adjusting;

② Remove the transmission, disassemble the clutch and check in sequence:

If there is oil stain on clutch disc, release bearing sleeve and conduit, it shall be cleaned in time;

If the working surface of clutch plate, pressure plate or flywheel is seriously worn, it should be replaced in time;

Check whether the pressure spring and diaphragm spring are weak, broken or have insufficient elasticity. If the elasticity is insufficient or damaged, replace them in time.

2. Incomplete clutch separation

(1) Fault phenomenon:

When the clutch pedal is pressed under the idling state of the vehicle, there is a gear impact sound when the vehicle is engaged, and it is difficult to engage.

Even if the gear is barely engaged, the engine shuts down before the clutch pedal is fully released.

(2) Possible causes:

The free stroke of clutch pedal is too large.

If it is hydraulic, it is not ruled out that the hydraulic system leaks oil, resulting in insufficient oil or air intrusion.

The newly replaced clutch plate is too thick or the front and back of the clutch plate are installed incorrectly (the convex side faces the transmission).

The pressure plate steel plate is warped, the friction plate is broken or the rivet is loose.

The height of the inner end of the release lever is difficult to adjust due to improper adjustment of the release lever, bending and deformation of the release lever, looseness of the support, and disengagement of the support shaft pin.

(3) Maintenance steps:

① Check whether the free stroke of the clutch pedal is appropriate. If the free stroke is too large, adjust it;

② Check the hydraulic system pipeline and pipe joint for oil leakage;

③ Check whether the installation direction of the clutch plate is correct, and replace it in time if it is deformed or damaged;

④ Check whether the release lever is deformed, whether the support is loose, and whether the release lever is adjusted properly;

⑤ Check whether the first shaft of the transmission and the driven plate of the clutch fit well. If the fit is improper, adjust it in time.

3. Abnormal clutch noise

(1) Fault phenomenon:

Abnormal sound occurs when the clutch is operated when the vehicle starts or shifts gears.

(2) Possible causes:

The pedal return spring is too soft, falling off or broken.

The rivet on the clutch plate is loose or the damping spring is broken.

The release bearing is seriously worn or short of oil, and the bearing return spring is too soft, broken or falling off.

(3) Maintenance steps:

① If you press the clutch pedal slightly and hear a "rustling" sound, and the sound disappears after lifting, it is the release bearing sound.

② If the sound still occurs after lifting the clutch pedal, it means that the bearing is worn, loose or damaged, and should be replaced;

③ If the clutch pedal is depressed or lifted, and there is intermittent knocking sound, replace the support spring.

4. The clutch shakes when the vehicle starts

(1) Fault phenomenon:

When the vehicle is in gear 1 and starts, the vehicle body shakes obviously.

(2) Possible causes:

The surface of clutch pressure plate or clutch plate is warped, or the rivet of driven plate is loose.

The fixing bolts of transmission and flywheel housing or clutch pressure plate and flywheel are loose.

The spring force of the damping spring on the clutch plate is uneven.

(3) Maintenance steps:

① Check whether the fixing screws of transmission and flywheel housing, clutch cover and flywheel are loose.

② Check whether the height of the diaphragm spring on the clutch pressure plate is consistent.

③ If the above items meet the requirements, remove the clutch and check whether the pressure plate and clutch plate are deformed, whether the rivets are loose and whether the elastic force of the diaphragm spring is within the allowable range.