Anybody figure out a way to rebuild an original factory U joint? I have a survivor that needs it.

Yup, VERY easy to fix.

Buy a new one and install...

With what is available if you look around,I wouldn't even bother.

Look around for a NOS one.

NOS & assembly line correct are not the same.

You may need to reuse your clips & keeper with a NOS joint.

But if it is a survivor & you plan to show it that way, just leave the old ones in place as is.

It's also a daily driver and is starting to vibrate a little. 75 Dart / 6. Yes, I like to enter it a survivor and it gets driven to shows.

take the shaft out & both ujoints should move smoothly by hand in their planes of travel (both ways on the front yoke/1 way on the rear ujoint). install the new one so the zerk is under compression & drive in the caps with a hammer & brass drift as opposed to a vise & use as few hammer strokes as possible (so stroke firmly). make sure the cross is positioned correctly side to side as you work each cap as you dont want any needles to fall over or get damaged. when done (likely) the ujoint movement will not be smooth so set the shaft on your bench & firmly whack each "ear" with a BFH/brass drift. there are (2) ears on each end & it is the sorta flat metal that connects the shaft with each ujoint "hole". hit each ear on each side about 3 good strokes then see if the ujoint moves freely & if not, hit each side again. when you go together check shaft end play into the trans (want ~3/4-7/8) when you go back together as too much will cause a vibration (usually part time). check trans extension housing bushing.