Clutch in engaged position (with the pedal released) should not "slip" and transmit torque from the engine to the transmission without loss, and when the clutch pedal is pressed, completely disconnect the transmission from the engine. The clutch engagement should be smooth, without jerks.
To complete the work you will need a ruler or tape measure. We carry out the work in the following order:
1. With the engine not running, press the clutch pedal several times. We make sure that there are no jams in the clutch release drive mechanism, and that there are no creaks, knocks or other extraneous noises.
2. Start the engine. If you hear a whining sound coming from the clutch housing that gets louder when you press the clutch pedal, the clutch release bearing is most likely worn out.
3. With the engine running, press the clutch pedal all the way down and engage the gear. The switch should be easy to turn on, without any crackling or crunching sounds. If you hear a crackling sound when engaging gears and it is difficult to disengage, this means that the clutch is not disengaging completely. We bleed the clutch release hydraulic drive. If there is no air in the drive, the malfunction may be caused by a malfunction of the clutch master cylinder, clutch slave cylinder, wear or loss of elasticity of the clutch diaphragm spring.
Recommendation. Since the release bearing and the clutch slave cylinder are made as a single part, if one of them fails, the entire unit will need to be replaced (see below). The work is labor-intensive, since it is necessary to remove the gearbox, so it is advisable to contact a specialized service station to fix the malfunction.
4. With the engine running and first gear engaged, gradually releasing the clutch pedal, check the smoothness of the clutch engagement, the absence of jerks or extraneous sounds when starting off. Jerks and rattling when the clutch is engaged can be caused by oiling or warping of the clutch discs or destruction of the torsional vibration damper.
5. While driving in third or fourth gear, sharply press the gas pedal. If the crankshaft speed increases quickly, but the car accelerates sluggishly, then the clutch is slipping. This is also indicated by the appearance of a burning smell in the cabin, emitted by the highly heated friction linings of the driven disk. To eliminate this malfunction, it is necessary to replace the clutch.
If the above signs of malfunction are not detected during the clutch diagnostics, the clutch is in good technical condition.
[Original version of the article on the website «CHEVYMAN.RU»]