How to repair the clutch car Ural

During vehicle operation, the following malfunctions may occur: incomplete engagement (clutch slips) or incomplete disengagement (clutch drags).

When the clutch engages incompletely, as the engine crankshaft speed increases, the vehicle does not start (with the clutch pedal released) or its speed increases very slowly.

A smell of burnt friction linings of the driven plates is felt in the cab.

The driven discs slip as a result of:

- absence of clearance between the clutch release bearing and the thrust ring when the clutch pedal is released.

When there is no clearance, the pressure plate does not fully press against the driven disc.

To eliminate this malfunction, ensure clearance between the release bearing and the thrust ring by checking and adjusting the free play of the clutch pedal;

- oil contamination of the clutch discs.

This malfunction occurs as a result of lubricant entering the clutch housing cavity through the seals of the gearbox input shaft or the rear end of the engine crankshaft, as well as when the clutch release bearing is excessively lubricated.

Lubricant getting on the friction surfaces of the discs causes them to slip. The clutch must be removed and the discs washed with petrol;

- wear of the friction linings and the friction surfaces of the flywheel, the intermediate driving disc and the pressure plate. With slight wear of the linings, the malfunction is eliminated by adjusting the free play of the clutch pedal.

With increased wear of the linings, the friction surfaces of the flywheel and the discs, replace the worn parts;

- settling or breakage of the pressure springs. Replace the springs.

When the clutch disengages incompletely, difficult gear engagement is felt, accompanied by impacts of the gear teeth of the gearbox. The malfunction can occur for the following reasons:

• presence of a large clearance between the clutch release bearing and the thrust ring. This happens because the clutch release mechanism does not provide the necessary travel of the clutch release fork shaft lever (reduced full travel, increased free play of the clutch pedal). The malfunction is eliminated by checking and adjusting the full or free play of the clutch pedal;
• misalignment or warping of the driven disc, uneven clearance between the discs due to their warping, and in some places even absence of clearance. This most often occurs when the clutch overheats due to slipping. Eliminate the malfunction by replacing the warped discs.

Destruction and tearing of the friction linings. Pieces of the lining become jammed between the driven and driving discs and prevent the clutch from disengaging completely. Replace the destroyed linings;

- misalignment of the pressure plate. When the clutch disengages, part of the working surface of the pressure plate continues to press against the driven disc.

Remove the pressure plate with cover assembly, install it on a special tool, check and adjust the position of the thrust ring.

Clutch removal

Remove the gearbox. Screw four clamping bolts 8 into the threaded holes of the pressure plate bosses 12 (Fig. 2) until the bolt heads contact the cover 10. Unscrew the clutch cover fixing bolts and remove the pressure plate 5 (see Fig. 1) with cover assembly.

Remove the driven discs 3 and the intermediate driving disc 2.

Adjusting the position of the clutch thrust ring

Install the pressure plate with cover assembly on the special tool 16 (see Fig. 2) or on the flywheel with an insert ensuring the installation dimension «А» equal to 29 ± 0.1 mm.

Secure the clutch cover 10 with bolts.

Loosen the clamping bolts 8 by unscrewing them two or three turns.

Bend open the edges of the locking plates 4 and unscrew the bolts 2.

Remove the plates 4, 1 and the lock washers 19.

By rotating the nuts 3, adjust the position of the thrust ring 7 of the release levers.

Dimension «В» after adjustment should be equal to 54 ± 0.3 mm, the runout of the end Т₂ of the thrust ring relative to the end Т₁ — no more than 0.4 mm.

The supporting surfaces of the ends of all release levers 14 must simultaneously contact the thrust ring.

Adjusting the position of the thrust ring after installing the clutch on the engine is prohibited.

After completing the adjustment, install (previously straightened) the lock washers 19. Install the support plates 1, plates 4 and secure them with bolts 2.

Bend the ends of the locking plates 4, thereby preventing the bolts 2 from unscrewing. Through the holes of plates 4 and 1, bend the lock washers 19.

Tighten the clamping bolts 8.

Unscrew the clutch cover fixing bolts and remove the pressure plate with cover assembly from the special tool 16.

Disassembly of the pressure plate with cover assembly

Bend open the edges of the locking plates 4 and unscrew the bolts 2. Remove the plates 4, 1 and the lock washers 19.

Install the pressure plate on a press and compress the clutch cover 10. Unscrew the clamping bolts 8 from the threaded holes of the pressure plate bosses.

Unscrew the adjusting nuts 3.

Using the press, relieve the force of the pressure springs and remove the clutch cover.

Remove the springs 9 and washers 11 installed on the pressure plate bosses together with the heat-insulating pads 13, as well as the thrust ring 7, the lock washers of the axles 18 connecting the release levers 14 to the pressure plate.

Drive out the axles and remove the levers with forks 15 and springs 5.

Remove the needle bearing rollers from the lever holes.

Remove the lock washers of the axles 17 connecting the release levers to the forks 15, and the springs 5 together with the loops 6.

Drive out the axles 17 and remove the lever forks. Remove the needle bearing rollers from the lever holes.

The intermediate driving disc 2 (see Fig. 1) should only be disassembled if it is necessary to grind the working friction surfaces or to replace parts of the automatic disc position adjustment mechanisms.

Disassembly of the clutch housing

Unscrew the clamping bolt of the lever 19 (see Fig. 3) and remove the lever from the clutch release fork shaft.

Disconnect the hose 6 (see Fig. 1), the clutch release bearing springs 7 and remove the release bearing 8 from the guide cover of the gearbox input shaft bearing. Unscrew the grease nipples from the threaded holes of the clutch housing.

Unscrew the clamping bolt 12 and move the fork 9 along the shaft 11.

Remove the segment key from the shaft groove.

Using a copper drift, drive the clutch release fork shaft 11 with the plug out of the clutch housing holes.

If it is necessary to replace the bushings, press them out using a mandrel, after first removing the clutch release fork shaft oil seal parts (cover, felt ring and rubber ring) from the hole of the left housing support.

Technical condition control and repair

After disassembly, wash the clutch parts in kerosene, dry them and determine their suitability for further use.

If the fastening of the hubs of the driven discs or friction linings is loose, re-rivet the rivets or replace them with new ones.

If the damper springs of the driven disc break or if the springs move axially in the disc holes, replace the driven disc assembly.

The following must also be replaced:

• friction linings of the driven discs in the presence of large gouges, delamination or wear down to the rivets;
• pressure springs in the presence of cracks and fractures;
• axles of the release levers having a brinelled working surface;
• worn needle bearing rollers. The dimensions of new friction linings and their holes for rivets must correspond to those shown in Fig. 4.

When checking the condition of the parts, check the change in elasticity of the clutch release bearing springs.

The force when stretching the spring to a length L = 115 mm must be at least 4.4 kgf.

Operation of the intermediate driving and pressure discs with through cracks and warping is not allowed.

At the same time, small thermal cracks on the friction surface of the discs are not a reason for rejection.

Warping, gouging, non-flatness and uneven wear of the friction surfaces of the intermediate driving and pressure discs can be eliminated by grinding.

The thickness of metal removed when grinding the pressure disc must not exceed 1.3 mm.

The thickness of the intermediate driving disc after grinding must be at least 23.66 mm.

If the wear of the bushings 2 (Fig. 5) of the clutch release fork shaft exceeds 25.1 mm in diameter, replace the bushings.

Replace the bushings using mandrels and a press.

When pressing, orient the ends of the bushings with chamfers towards each other, and align the holes in the bushings and housing supports for lubrication.

Machine the inner surfaces of the pressed bushings in line to a diameter of 25^+0.025.

Check the misalignment of the machined holes of the bushings with a 24.99 mm diameter gauge.

The non-parallelism of the common axis of the bushings and the end face «Т» must not exceed 0.1 mm over a length of 100 mm.

If the clutch release bearing is replaced, press the new bearing on until the inner ring contacts the end face of the release bearing.

Assemble the clutch housing and the intermediate driving disc in the reverse order of disassembly.

When assembling the intermediate driving disc, apply Litol-24 lubricant to the friction surfaces of the axles and bushings of the release levers. After tightening the axles of the release levers, bend the lock washers on both sides.

After assembly, check the operation of the automatic adjustment mechanisms of the intermediate driving disc position.

When placing the disc on the plate, the springs of the release levers must not twist under the weight of the disc and must return the disc to its original position after pressing it until it contacts the plate.

When installing the lever 19 (see Fig. 3) on the splines of the clutch release fork shaft, ensure that the marked tooth of the lever enters the marked groove of the shaft (marks b).

Assembly of the pressure plate with cover

Before assembly, the parts must be dry and clean.

When assembling, lubricate the spherical friction surfaces of the adjusting nuts 3 (see Fig. 2), the clutch cover 10, the release levers 14 and the working grooves of the thrust ring 7, as well as the needle bearing rollers, with Litol-24 lubricant.

During the assembly of the pressure plate and adjustment of the position of the thrust ring of the release levers, monitor the cleanliness of the working surfaces of the special tool 16.

Ingress of dirt and metal chips onto the friction surface of the pressure plate and the flange of the clutch cover is unacceptable.

Assemble the pressure plate in the following order.

Install 20 needle bearing rollers for axle 17 into the hole of the release lever 14.

To facilitate the assembly of the needle bearing, apply a thin layer of Litol-24 lubricant to the wall of the release lever hole and install six to eight rollers into the hole.

Then insert a split textolite bushing (Fig. 6) into the lever hole and install the remaining rollers.

When installing a new needle bearing, assemble it from rollers of the same size group.

After aligning the holes of the fork 15 (see Fig. 2) and the lever 14, insert the axle 17, thereby pushing the split bushing out of the lever and fork holes.

Similarly, using the split bushing, assemble the second needle bearing and install the release lever into the groove of the pressure plate boss.

After aligning the lever hole with the boss holes, insert the axle 18, thereby pushing the split bushing out of the lever and boss holes.

Install lock washers into the annular grooves of axle 18.

Install spring 5 together with loop 6 onto axle 17, and lock washers into the annular grooves of the axle.

Similarly, install and secure the remaining release levers and thrust ring springs. Install and secure the thrust ring 7 with loops 6.

Install the pre-assembled pressure plate on the special tool 16 or on the flywheel with an insert ensuring the installation dimension «А» equal to 29 ± 0.1 mm.

Install washers 11 together with heat-insulating pads 13 and pressure springs 9 onto the pressure plate bosses.

If the working surface of the pressure plate has been ground, place metal washers under the heat-insulating pads to maintain the total force of the pressure springs.

The thickness of the washers must equal the thickness of metal removed during grinding of the disc.

Install the clutch cover onto the pressure springs. Ensure the vertical position of the forks 15 of the release levers and compress the springs using a press.

Secure the clutch cover with bolts. Tubes installed through the holes of the clutch cover onto the threaded ends of the forks can be used as a means of ensuring the vertical position of the release lever forks.

Screw in the nuts 3 and use them to adjust the position of the thrust ring 7 of the release levers.

After completing the adjustment, install (previously straightened) the lock washers 19. Install the support plates 1, plates 4 and secure them with bolts 2.

Bend the ends of the locking plates onto the faces of the fixing bolts. Through the holes of plates 4 and 1, bend the lock washers 19.

Screw four clamping bolts 8 into the threaded holes of the pressure plate bosses. Unscrew the clutch cover fixing bolts and remove the pressure plate with cover assembly from the special tool.

Installing the clutch on the engine

Before installing the clutch, place 15 g of lubricant 158 into the cavity of the rear end of the crankshaft (under the front bearing of the gearbox input shaft).

Wipe the friction surfaces of the flywheel, the intermediate driving disc and the pressure plate with a clean cloth slightly moistened with petrol.

Install the driven disc 3 (see Fig. 1) into the flywheel so that the longer part of the disc hub faces the engine.

Apply Litol-24 lubricant to the working friction surfaces of the release levers of the intermediate driving disc 2 and insert the disc into the flywheel. The disc lugs must enter the grooves of the flywheel.

When pressing on the disc, it should move easily in the flywheel grooves and return to its original position under the action of the release levers.

Install the second driven disc 3, placing the long part of the disc hub away from the engine.

Centre the driven discs relative to the engine crankshaft axis using a splined mandrel, inserting its end into the hole of the front bearing of the gearbox input shaft.

Install the pressure plate with cover assembly and secure the clutch cover with bolts. After securing the cover, unscrew the four clamping bolts.

Install and secure the gearbox.

Check the quality of the installation of the clutch and gearbox on a running engine at a crankshaft speed of 1800-2000 rpm, checking:

• the absence of jamming of the parts of the clutch release mechanism (control);
• the cleanliness of clutch disengagement when the pedal is fully depressed. In this position of the clutch pedal, engaging 1st gear and reverse gear should be done without grinding, and when 4th gear is engaged, the secondary shaft should not rotate.

Adjustment of the full and free play of the clutch pedal. The full travel of pedal 2 (Fig. 3), which should be 195 mm, is adjusted using the stop 12.

To adjust the free play of the clutch pedal, disconnect the rod 17 from the lever 19. Loosen the lock nut of the rod fork.

By rotating the fork in the required direction, change the length of the rod 17 to increase or decrease the clearance between the ends of the thrust ring and the clutch release bearing.

Connect the rod to the lever 19 and check the amount of free play of the clutch pedal. If it corresponds to 30-40 mm, tighten the lock nut of the fork.

It is permissible to move the lever 19 by one spline on the shaft (relative to the marks b located on the ends of the shaft and the lever) if the thread of the rod 17 is fully used during adjustment.

Also see the article «Clutch of the KamAZ vehicle», as the clutch is basically the same.