I am doing a preventative replacement of rear drive shaft U joints on a '78 F250. The old joints pressed out clean. The new joints pressed in clean but I could barely get the clips in. It is tight on both ends and the joint feels tight. I believe the caps are butted up tight against the cross. Should I be worried or will some use loosen things up?

The only fix I can think of is to start over and remove a little material from the top of the caps to create some small clearance (belt sander).

Advice and suggestions welcome.

 

If the clips are in and the u-joint moves, though tight, here is what I do.

I Take a 3-4 pound brass hammer (or any soft, metal hammer) and "stress relieve" the u-joint yoke, hitting mainly on the sides of the bearing caps, while holding the drive shaft in my hand. 4-6 good whacks on each side of each bearing cap should free the u-joint up.

Good luck.

Roger Carter

 

Clips are in and seated. I'll give the brass hammer a try. Thanks!

 

X2 on some love taps . If all is right , that will free it up .

 

Well, I worked it over with a 2 lb brass hammer and still no good. On the way home I stopped at AZ and picked up a new "gold" u-joint to replace the NAPA premium joint I had installed unsuccessfully.

This time I measured the span from cap to cap with a digital caliper while squeezing the caps together with finger pressure. Here is what I found (average 3 measurements) :

Old Joint: 3.63"
New NAPA Premium Joint: 3.66"
New AZ Gold Joint: 3.63"

The NAPA premium joint runs big which was likely my problem. I worked my one un-installed NAPA joint over with the belt sander to get it down to size, installed it and it turns free. I'll go ahead and install the AZ joint without the belt sander treatment.

The NAPA joint is a FM piece. Its greasable through the cap with internal passages to distribute to the other caps. Its a nice design but not when dimensions are not correct. I think I will use AZ from now on for these.