How much of a bind is acceptable before hammering? If I get the caps to where the clips just barely fit comfortably, the joint is almost too tight to turn by hand.

 

check and see it another needle bearing fell out and is stuck to the top of the cap.
You should not need a hammer at all to get them back in.

 

They can be very tight.

I've never been able to get both snap rings in when I had a trapped needle.
Not "should not". I never use a hammer to install bearing caps.

 

Needle bearings were still in place every time I had to remove and redo a joint.

 

and your pressing the cap into yolk using a socket or something like that?

 

I didnt install with the hammer per se. I pressed them in till the circlips almost fit. I then used a socket and small hammer to tap the caps a teensy bit more so all clip edges would go in the groove.

Antichrist: what causes the bind that can be relieved by a rubber mallet?

 

I have always WAY over seated first cap. In other words, press in first cap until it is almost through inside of yoke. This alows fully seated spider to maintain needle bearings on both sides. Install first circ-clip, then install second cap and clip.
As to what causes vibration that can be cured with rubber mallet, I believe (and note, it is a belief, nothing I've ever proven) the brand new perfect u-joints need to find their true center. A little driving and centrifigul force will achieve the same result. I recently did the front u-joint on the front drive shaft, simply because the existing one would not emit grease from all four seals. The brand new Neapco produced a slight growl in the front diff on decelleration, and I suppose the overall vibration is now worse than before. I suspect this is due to new, tighter components. The diff is freshly filled with 85W140. The growl went away after 20 to 30 miles of driving, and the minor (I'm very in-tune with the Disco) vibration continues to improve.
My lap top died, and this pc has no spell check. Apologize for errors.

 

The end of the journal being pressed tight against the inside of the cap, usually because one cap isn't tight against the snap ring. Tapping the yoke shifts the caps tightly against the snap rings.

 

Interesting. Just to be sure I am understanding...

- you push a cap in way too far and put in the clip
- put the opposite cap on and push in until the first cap hits the clip
- at this point, the other clip can go in, otherwise, press until it fits

Easy peasy japanesey?

If my first attempt tonight doesnt work, Ill try this method instead of pressing the joint all the way out and starting over.

 

That makes sense.

What doesnt make sense is the fact that mine gets to that point before the caps are seated enough to get the clips in the races comfortably.