Hi guys.

I was driving to town today (in my '89 4x4 F250 with 7.3 diesel) to have a local shop replace my ball joints. I noticed a tell tale 'clunk' when I stepped on the accelerator. Grr.

I asked the guy in the garage to check the driveshaft U joints. Sure enough, he said the middle one was bad. I've replaced U joints on this truck several times before, and figured I was paying the shop muchos dollars to do the ball joints, so I maybe I'd replace this myself. I picked up a replacement U-joint before coming home.

I pulled out the drive shaft, and two of the bearing cups on the middle U joint appeared to have lost all their little rollers. I removed the retaining clips and sprayed the cups with penetrating oil and figured I will press them out in the morning.

Then I took a close look at the middle shaft supporting bearing. It seems to have a circular rubber suspension that sits in the arched housing that supports the center of the shaft. That rubber suspension has an outer circular ring and an inner ring with sort of spoke-like radial rubber connectors between. A bunch of the radial connectors appear to be broken.

Should I be concerned about this rubber suspension? Maybe this has something to do with the number of times I have replaced U joints?

How do you get this damn thing off the shaft? Do I have to snip the crimp-on bands and take the rubber accordion boot apart? My Haines manual tells me nothing about this. Anybody have experience?

 

I've had a truck with a 2-piece driveshaft like that...that rubber support bushing soaks up driveline vibrations, probably an attempt to keep them away from the bearings and u-joints. I'd replace it while it's apart.

I don't remember having to take the boot off, but this was a few years ago so I could be wrong.

 

The front, shorter driveshaft should pull out of the rear part of the driveshaft. It's a splined connection, which sometimes ends up getting stuck due to corrosion.

When I did mine last year, I had to use an air hammer and plenty of penetrant to separate the two drive shafts. Once that was done, I used the air hammer to remove the center bearing from the rear shaft.

 

the center "rubber support" you are referring to is called a carrier bearing, and it needs to be pressed off and back on.