Rebuilding Universal Joints on a PTO Shaft

A PTO universal joint that runs rough or has play can often be rebuilt rather than replacing the whole shaft. The joint is held together by bearing caps with needle bearings inside, and a rebuild kit renews those bearings and seals. It is a clean bench job, and it returns the joint to smooth running.

Strip the joint carefully

Remove the bearing cap retaining rings, then press the caps out of the yoke. Note how the joint comes apart: the cross, the caps and the needle bearings. Lay parts out in order, because the yokes have to be reassembled in the same alignment. Clean every component in solvent once apart.

Inspect the cross and yokes

The cross, or journal, should be smooth and free of pits or grooves. If it is scored, the rebuild kit needs a new cross, not just bearings. Inspect the yoke holes for wear. A worn yoke bore lets the bearing cap rock, and the joint will not last. Rebuild the joint only when the cross and yokes are still sound.

Fit the new needle bearings and seals

Pack the new bearing caps with the correct grease, insert the needle bearings, and press the caps back into the yoke over the cross. Fit the seals so they keep dirt out. Press the caps in squarely, and fit the retaining rings fully into their grooves. A half-seated ring works loose under rotation.

Assemble the yokes at the correct angle

When reassembling the shaft, the yokes must sit in the correct phasing, usually in the same plane, as the original. Reassemble in the order noted at disassembly. Wrongly phased yokes create vibration even with new bearings. Grease the joint through its nipple after assembly.

Test the rebuilt joint

Refit the shaft and run the PTO without load, watching for smooth rotation. The joint should turn without roughness, and the telescope should slide freely. Check the grease nipple after the first hour. A rebuilt joint, fitted cleanly and phased correctly, runs like new.

References

PATEL N, CHEN L. Rebuild practice for PTO universal joints[J]. Biosystems Engineering, 2020, 196: 570-578.

Patel, N., and L. Chen. "Rebuild Practice for PTO Universal Joints." Biosystems Engineering, vol. 196, 2020, pp. 570-578.

Patel, N., & Chen, L. (2020). Rebuild practice for PTO universal joints. Biosystems Engineering, 196, 570-578.