Drive shaft overhaul. Part 1

(AndyBlakey) #1

Recently my XJ6 turned 130K miles and duly developed a noisy driveshaft center bearing. With a few days off work I made a project of replacing the bearing. This is going to be a DIY effort in that the car will be raised on stands. I have bought some specialist tools though. So here’s how it went…

First thing I did was mark everything up. The orientation of all parts must be preserved as the driveshaft was balanced at the factory after assembly. Then removed the heat shield. I was able to do this without disassembling the exhaust.

The transmission output flange bolts are not easy to reach. I had to use a 12" extension, universal joint, and a slim walled 9/16" socket passed over the transmission mount to reach the nuts. Then an open ended wrench from the side to stop the bolt from turning.
Along the way make note of the position of the rear bearing in relation to its support plate using the bolt heads.

and do the same for the position of the mounting plate to the bottom of the car.

One thing I wasn’t prepared for. The drive shaft assembly is surprisingly heavy. Be careful and be prepared if you are working under the car alone.
I finally had the driveshaft on the floor of the garage. The U-Joints don’t feel bad but the centre bearing has definitely been running dry. The rubber support is splitting too.

There are plenty of videos on youtube showing ‘How to replace U-Joints’ many involving hammers and beating the old joints out. I’m against these methods. The risk is bending an ear on the propshaft. Which will ruin the propshaft completely or create a vibration that can’t be rectified. I used a puller, and a U-Joint press kit to try and do things gently. The press kit was cheap and probably wouldn’t last long in a shop but I may never use it again. It did the job.
The puller is oversize having been bought to do something else, but did work and I wasn’t going to buy a smaller one just for this job. It was a little heavy to use but worked. You really don’t need anything this big though. It was good for pulling the old centre bearing off too.
First make sure all parts are marked and remove the retaining clips. Buy a pair of proper circlip pliers. It’s the easiest way to do it. I also found that the three sets of retaining clips supplied with the new U-Joints were all thicker than the OEM clips and could not be used. So you may want to remove the old clips without damaging them.

All the force of pushing the cup out goes straight through the socket and puller. No risk of bending the ear like this. All four cups of the old joints are removed in this way.

Depending on the design of the joints that you are removing, you might find yourself in this position. The shoulder of the bearing cross meets the inner edge of the ear before the bearing cup is pushed out far enough to remove it. Be careful if this happens because the bearing cross will dig a burr into the edge of the yoke ear. I did this once and had to file the burr down before refitting the new joint. It’s not a major problem but not desirable either. Having done it once I was more careful while removing the second and third joint.

You may also find that the bearing cross hasn’t enough range of movement to push the bearing cups right out. If so pull the opposing side too then see if you can push a small nut or some washers into a cap then try again.

A pair of heavy pump pliers may also be useful to twist a bearing out.

I was a bit concerned that the puller would slip off the trunnions but provided the puller is lined up well with the axis of the joint this was not a problem. This isn’t good for the bearing surfaces but these joints are headed for the scrap bin anyway.

All three u-joints were removed in a similar fashion.