The cardan gear consists of an intermediate cardan shaft, an intermediate support, a rear cardan shaft and three cardan joints
The intermediate cardan shaft is made of thin-walled steel pipe.
A shank with external splines is welded to the rear end of the intermediate shaft, and a fork is welded to the front end, to which a sliding front fork with an internal splined hole and a dirt deflector is attached through the cardan joint.
Front fork (shank) is inserted into the extension of the rear gearbox housing and engages with the splines of the output shaft.
During the operation of the rear suspension, a longitudinal displacement of the driveline occurs. At the same time, the shank, moving along the splines of the secondary shaft of the gearbox, compensates for these shifts.
The spline connection is lubricated with oil poured into the gearbox housing.
Intermediate support is a rubber corrugated element; a closed ball bearing is vulcanized to it from the inside, and a bracket from the outside.
The rubber layer prevents the transmission of vibrations to the body and allows the driveline to move along the longitudinal axis of the car. The intermediate support bracket is bolted to the frame cross member.
The support bearing does not require maintenance throughout its entire service life.
The rear cardan shaft is made of a thin-walled pipe with forks welded to the ends.
A splined fork of the middle joint is attached to the front of the shaft through the universal joint. It is put on the rear spline of the intermediate shaft after the intermediate support.
It is fixed from displacements along the slots with a bolt with a lock washer.
A flange with a centering belt is attached to the other part of the rear propeller shaft through the hinge cross. It is attached with four bolts to the flange of the final drive gear.
Universal Joint consists of forks and cross with four sealed needle bearings. Each of them has 20 rollers (needles) with a diameter of 2 mm.
The needles are made with high precision, matched to this bearing assembly with the cross and are not interchangeable for different bearings.
Therefore, it is unacceptable to replace only the cross or bearings, the entire set is replaced as an assembly, even if at least one bearing is damaged. A grease fitting is screwed into the cross.
From it, the oil pumped by a grease gun flows through the internal channels to the bearings.
The oil is retained inside the bearings by a rubber cuff with a spring. When "syringing" the universal joint, the spring stretches and excess oil flows out.
Needle bearings are pressed into the coaxial holes of the forks and fixed in them with snap rings.
The cardan joints of all GAZ vehicles are traditionally lubricated with gear oil. This is not very convenient, you often have to squirt the connection. Fill the bearings with #158 grease and you can forget about their existence for a long time.
When repairing the driveline you find that the wear of the cross is small and it will still serve, turn it 180˚ around one of the axes of the spikes and assemble the joint in this position. The spikes will work on the non-worn side and the resource of the node will almost double.
Maximum allowable radial play of cross bearings, mm......0.1
Maximum allowable runout of the cardan shaft pipe, mm.....0.6
Runout of pinion flange seating band 0.15
Gearbox output shaft runout 0.15
Possible gimbal failures. Their causes and remedies
- Cause of malfunction
Knocking in the driveline during a sudden change in vehicle movement or when shifting gears:
- Wear of bearings and spikes of crosses in hinges
Check radial clearance in pivot bearings and if greater than 0.10 mm, replace spider and bearings
- Loose fastening of the shaft to the flange of the rear axle drive gear
Tighten the fastener to the specified torque
- Lost balance plate
Dynamic shaft balancing
- The spline fork of the intermediate shaft
Install the slotted fork in the same plane as the sliding fork
- The fastening of the intermediate support to the cross member has loosened
Increased runout of sliding fork in gearbox extension:
- Wear or breakage of one of the hinges
Initially turn the spline fork 180° and check if the runout is reduced. If it does not decrease, replace worn parts. When replacing the spline fork, balance the shaft dynamically
- Breakage or damage to the rear axle drive gear flange
- Cardan shaft tube is bent or removed
- Shaft fastening to the rear axle has loosened
Inspect the shaft, check its runout and, if it exceeds 0.8 mm, straighten it, while its runout should be no more than 0.6 mm at any point along the length. Balance the shaft dynamically. Tighten the mount
Faults that are detected during inspection:
- Turning the cap with the cuff relative to the bearing cup (violation of the tightness of the hinge)
Replace cross with bearing assembly. Balance transmission
- Turning the bearing cup in the fork holes
Replace worn parts, balance gear