Rebuilding the Datsun 240Z half shafts or Drive Shafts (per Datsun FSM) – is indeed a do-it-yourself project. There are tons of references on the internet, and I’ve made several of the links available below.
I have rebuilt the half shafts in my 1971 Datsun 240Z. I took a bunch of photos of the dis-assembly and re-assembly, and added copious notes about my experience.
Inspect all the parts when you get them. I received 4 boxes of 393 u-joints, but only 3 actual 393 u-joints. One had 29mm caps instead of 28mm. Called local O’reilly retail store (Friday 11am), and did a straight exchange over-the-counter Saturday at 11am – just as the promised!
Jack the rear of the car onto axle stands. You will need to remove the 8 bolts (4 at each end) that secure the half-shaft at the differential end and at the rear wheel. If you start by the wheel, leave two bolts & nuts in place (finger tight) so the half-shaft is not flopping around while you try to remove the bolts at the other end. Not an issue if you start at the differential end.
FSM Removing the Drive Shaft
You will need to remove one bolt, spin the shaft, remove one bolt, spin the shaft, repeat.
The connection at the differential end required some work with my 2.5 pound sledge hammer to get the two parts to separate. There isn’t a lot of ‘swinging room’ and the joint is very near the diff, so be careful and patient. Many years and a little bit of rust is all it takes.
U-Joints came out easily (large hammer method). The bearings were loose, not sloppy, just loose. The seals most likely were shot - very little grease left - and examining the underside of the car it was clear these had been slinging grease.
Rubber Boot step 3 of 3 - now turn the Rubber Boot right-side-out and start to pull it back off the Drive Shaft. Only pull until the end (in the red circle) flips right-side-out as shown here. Then slide it back into position.
Liberally grease the inside of the Sleeve Yoke. In particular, the tracks that will hold the ball bearings. IMPORTANT, the tracks that accept the bearings are marked with the red arrows. (NOTE: The Drive Shaft is inserted in the OTHER end of the Sleeve Yoke (not the end shown here!)
Carefully slide the Drive Shaft into the proper end of the Sleeve Yoke. Keep the alignment so the U-joint mounts are in the same orientation. If you can have someone hold or otherwise secure the Sleeve Yoke, it would be helpful. Slowly work the bearings and Drive Shaft in. This takes time and patience. Insert the bearing retainer and snap ring.
Push the Drive Shaft so the end sticks out the back of the Sleeve Yoke. Install the Drive Shaft Stopper and snap ring. IMPORTANT: The Drive Shaft Stopper is free to rotate - be sure to align it in the same channels as the ball bearings are in before you push the shaft back in. Add extra grease and install the Sleeve Yoke Plug and clip ring.