New member / with Vibration

[Mastif]

Hey guys, new member here with a pretty bad Vibration, here is some history.
Car is a 69 GTS, 340 4 speed, 3.55 sure grip 8 3/4 rear end.
I removed the drive shaft to take it for a balance/bent checking, and when I removed it I found the U-Joint caps that seat in the yoke was very hard to remove, I had to pry them out. and when you put them back in place, they will not fit back in as if they are too large around. Only when you tighten up the U-bolts, it will pull them back in to seat up and rest in place. Seems to be the wrong caps.
Any thoughts?
Also, I will add a few pictures of the car and details later this week introducing myself.
Thanks for any input.
Mark

 

[Supershafts]

Depending what end yoke you have it might be normal, some aftermarket end yokes are close in lock up dimensions.

Also if it's a SPL style joint the triple style will put some pressure on the caps pushing outward and need some effort to squeeze them and seat them in the end yoke.
However u-bolts sounds like you have aftermarket end yoke and this is normal, just do not tighten the u-bolts more than 20 ft lbs like most do and crush the caps and cause issues with the joints needles and cross.

.

 

[Mastif]

Thanks for the response. It may be normal as you say, but after doing a little research, I think maybe I have the wrong yoke on the rear end, and need a #7260 size cap on the u-joint that fits into the yoke. Is this possible? I do know the caps for a Spicer #5-1306 is just a little smaller in diameter, does have the C-clip, and will fit my current joint.
Thoughts?

 

[Supershafts]

Take a pic of the yoke you have head on and one from the side then i'll know exactly what you have, but the u-bolts lead me to stay with my original