Coupling is located between the engine and a transmission and intended for short-term separation and smooth connection of a cranked shaft of the engine and primary shaft of a transmission that is necessary for a car troganiye from a place and for gear shifting without noise and risk of damage of details.

Fig. 8.1. Coupling: 1–flywheel; 2–coupling disk; 3–press disk; 4–bearing of switching off of coupling; 5–a fixing spring; 6–fork of switching off of coupling; 7–a hairpin with a spherical finger; 8–protective cover

On all models dry one-disk coupling which consists of conducted and press disks of coupling, the central diafragmenny spring, a casing and the bearing of switching off of coupling (fig. 8.1) is established .

The conducted disk of coupling freely moves on shlitsa of primary shaft of a transmission and is clamped between a flywheel and a press disk effort which is created by the central diafragmenny spring. From two parties of a conducted disk приклепаны frictional slips. The conducted disk of coupling incorporates to a nave through details of a quencher of krutilny fluctuations. Need of a quencher of krutilny fluctuations is caused by the following.

At sharp change of speed of movement of the car, arrival on roughness of the road, sharp inclusion of coupling, and also owing to non-uniform operation of the engine in transmission of the car there are the dynamic loadings causing a twisting (raskruchivaniye) of shaft of transmission. Unevenness of a torque of the engine can cause considerable overloads in transmission owing to emergence of krutilny fluctuations and a resonance at coincidence of the frequencies, being transferred loadings to frequencies of own fluctuations of transmission. Elastic fluctuations of transmission lead not only to noise emergence in mechanisms and units, but also to dangerous vibrations, and sometimes and to breakages of details when the amplitude of fluctuations reaches big size. The quencher is necessary for absorption of energy of krutilny fluctuations.

Drive of switching off of coupling the hydraulic. The bearing of switching off of coupling is established from the forward party of a transmission on the coupling of switching off of coupling. The bearing will mix up a fork of switching off of coupling. By pressing a pedal of coupling the piston in the main cylinder moves and compresses liquid which on a hose arrives in the working cylinder of coupling. Under pressure the piston of the working cylinder of coupling, moving, puts in action a fork of switching off of coupling. The fork of switching off of coupling moves the bearing which influences a spring of a press disk and takes away press a disk from a conducted disk of coupling. Coupling is regulated automatically.

Before replacement of components which obviously failed, that продиагностировать malfunction of coupling and its drive, execute the following preliminary checks:

Check level of brake liquid in a tank of brake system which also serves as the tank for a hydraulic drive of coupling.

If level is lower demanded, add liquid and check hydraulic system on absence of leakages of brake liquid.

At operation of the engine idling and the gear shifting lever in neutral situation press a pedal of coupling and in some seconds include any transfer, thus from a transmission it should not be audible any noise. If there is an increased noise at transfer inclusion, probably, press the disk and/or a disk of coupling have defects.

For check of complete switching off of coupling start up the engine, tighten the parking brake, press a coupling pedal so that it did not reach a floor on 10–15 mm, and several times switch on and off the first transfer. If transfer joins hardly, check a course of a pusher of the main cylinder of coupling and liquid level in a tank of brake system.

Visually check the plug of a pedal of the coupling, located in the top part of a pedal, on absence excessive люфта and jammings.

From below the car check that the fork of switching off of coupling is established on a hairpin with a spherical finger.