Bearings and journals are the parts most likely to wear and these should be inspected. Should any evidence of damage or wear be noticeable then the cross and bearings should be renewed as worn parts will cause vibration of the driveline shaft.
If an inspection indicates that the universal joint is suitable for re-use, then all old lubricant should be removed and the cavities in the cross-packed with new lubricant. The bearings should be cleaned and re-lubricated and the sealing washers renewed to prevent the escape of lubricant.
As the bearings are subjected to a very limited amount of movement, this will eventually cause pitting of the bearing surfaces and needles, usually on the thrust side only.
Bearings subjected to such limited movement suffer from what is known as ‘fret corrosion’.
The probable reason for this is that rollers do not move sufficiently to roll on the lubricant, but can actually come into dry contact with bearing surfaces.
The method of reassembly is, in the main, the reverse of the dismantling sequence.
- Insert the cross into the yoke.
- Using a soft drift, slightly smaller in diameter than the bearing, tap the bearing into position. Alternatively, lightly press the bearing into position. The bearing should not be a free fit in the hole in the yoke.
- Repeat this for the other three bearings and refit the snap rings.
- If the joint appears to bind after reassembly, it can be tapped lightly with a soft faced hammer to relieve any pressure of the bearings on the ends of the cross.
- Where applicable, reassemble the slip splines making sure that the yokes at the front and rear of the shaft are in correct alignment. Refer to the identifying arrows on the shaft and sleeve.
- When installing the drive shaft, ensure that the flanges are clean to prevent shaft run-out.