The clutch of the ZIL-131 car is single-disk, dry, installed in a cast iron crankcase 8

The clutch cover 9 is fixed on the flywheel 2 of the crankshaft 1 with eight centering (special) bolts 23

The clutch pressure force is generated by sixteen springs 7 installed between the clutch cover 9 and the pressure plate 3.

Heat-insulating rings 10 are placed under the springs on the side of the pressure plate.

ZIL-131 clutch

The transmission of torque from the casing 9 of the clutch to the driven disk is carried out through the pressure disk 3 by four pairs of spring plates 4.

The plates create a rigid connection between the pressure plate and the clutch housing in the circumferential and radial directions, while at the same time allowing the pressure plate to move relative to the clutch housing in the axial direction due to its flexibility, which is necessary for disengaging and engaging the clutch.

The plates are attached to the casing on one side, and on the other side, with the help of special bushings 5 ​​and bolts 6, to the pressure plate.

The switching device consists of four levers 16, which are connected with the fingers 20 to the pressure plate and the fork 18.

Between the fingers 20 and the lever 16, needle rollers 22 are placed. The fulcrum of the levers on the casing are the adjusting nuts 17, screwed onto the threaded ends of the forks.

The nuts are pressed against the clutch casing by elastic plates 19, each of which is fixed to the casing with two bolts.

Clutch driven disc

The elasticity of the plates 19 and the spherical bearing surface of the nuts in contact with the casing allow the forks 18 to make small rocking movements when disengaging and engaging the clutch.

The position of the clutch release levers 16 is adjusted by the nuts 17, which are punched after adjustment. During the operation of the car, these levers do not regulate.

The clutch disc is steel, with friction linings, it has a torsional vibration damper (damper) of a friction type (with dry friction of steel on steel).

The damper's elastic coupling consists of eight springs 2 evenly spaced around the circumference (Fig. 2).

Each spring, together with two support plates 3, is placed in holes punched in the driven disk 1 and the damper disks 5.

Base plate 3 has four lateral protrusions that hold it in the holes of the driven disk, and a flared hole on which the spring is centered.

The hub 6 of the driven disk, together with the damper disks riveted to it on both sides and oil deflectors 4, can rotate relative to the driven disk in both directions at a certain angle; in this case, the springs are compressed.

The maximum angle of twist is determined by the full compression of the springs until the coils touch. The driven disk 1 is centered on the outer diameter of the hub flange 6.

The driven disk is balanced. Balancing is carried out by installing balancing plates on the driven disk 10, the allowable imbalance is 25 gcm.

To disengage the clutch, the pedal is mounted on a bracket attached to the left side member of the vehicle frame.

The lower end of the pedal is connected by an adjustable rod 5 (Fig. 3) to the lever 3 of the clutch release fork.

Pedal travel is limited to the floor of the cab. The clutch release fork 15 (see Fig. 1) moves the clutch 12, on which the bearing 11 is installed.

The bearing, pressing the ends of the levers 16, turns off the clutch.

Clutch disengagement bearing 11 has a constant supply of lubricant, which is put in at the bearing manufacturer, and is not lubricated during operation and repair.

If necessary, this bearing is replaced with a new one.

In the lower part of the cover 21 of the clutch housing there is a shield 25 of the oil sump and a plug 24 with a cotter pin to drain the oil that enters the clutch housing from the gearbox.

The clutch is adapted to overcome deep fords.

To seal the clutch before fording, plug 24 must be replaced with a blind plug, which, during normal operation, is screwed into the bearing cap of the drive spur gear of the front axle reduction gear.

A sealing gasket 28 is installed between the clutch housing 8 and the cover 21 of the clutch housing; the sealing gasket is also installed under the flange of the fork 15 of the clutch release; both gaskets are installed on the sealing paste.

The front and rear ends of the clutch housing were sealed with the same paste when assembling the power unit.

To seal the fork 15 for disengaging the clutch, rubber rings 34 are installed on its necks on both sides.

At the bottom of the front end of the clutch housing there is a special rubberized shield 29 that closes the opening in the crankcase with clinging.

The shield is attached to the clutch housing with two bolts and is pressed into the lower plane of the cylinder block by a protrusion on the front of the clutch housing cover.

When assembling, you must first tighten the shield mounting bolts until the bolt head touches the spring washer, without completely tightening them, then tighten the clutch housing cover 21 bolts and only then finally tighten the shield mounting bolts.

Clutch actuator adjustment

A properly adjusted clutch should not slip in the on position, and when you press the pedal, it should turn off completely (should not “lead”).

The working stroke of the pedal should be 130-150 mm, the free play 35-50 mm, and the total travel should be at least 180 mm

ZIL-131 clutch drive

As the friction linings wear, the free travel of the clutch pedal decreases, causing the clutch to slip. This leads to rapid wear of the driven disc and the clutch release bearing.

In case of excessive free play (over 35-50 mm), when you press the pedal to failure, the clutch does not fully disengage. This leads to rapid wear of the driven disk and makes it difficult to shift gears.

The pedal free play must be adjusted in the following order:

  • 1. Loosen locknut 2 (Fig. 3).
  • 2. Adjust the free travel of the clutch pedal by turning the spherical adjusting nut 1; to reduce the free play of the pedal, screw the spherical nut onto the rod 5, and to increase the free play, turn it off the rod.
  • 3. Tighten locknut.
  • 4. After adjustment, start the engine and check that the clutch works correctly.

With a properly adjusted clutch drive, the gap between the ends of the levers 16 (see Fig. 1) and the clutch release bearing should be 3-4 mm.

Clutch care

Care consists in periodic adjustment of the clutch drive, cleaning of dirt, timely tightening of all bolted connections, lubrication of the clutch release fork and clutch pedal shaft in accordance with the lubrication map.

The front bearing 31 of the input shaft of the gearbox has a constant supply of grease, which is put in at the bearing manufacturer, and is not lubricated during operation.

During repair work, this bearing is replaced if necessary with a new one.

It is necessary to carefully monitor the tightening of the bolts securing the crankcase to the cylinder block.

The tightening torque of the bolts should be 8-10 kgm. The bolt must be tightened evenly, consistently, crosswise.