universal joint fitment issue

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roylerumble

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I've rebuilt a 8 3/4 rear that I'm installing in my 69 valiant. It isn't the rear it came with (someone previously transplanted a 340 and 8 3/4). The first problem I encountered was the U joint in the propeller/drive shaft mating to the rear. The U joint on the drive shaft yoke was way to small to fit the pinion. I solved that problem, sort of, I found a thread on conversion universal joints and sourced one out. I've pressed the old one out, and the new one in, but now the problem is that the only one of the cups will seat in correctly. It seems the c clip that fit the cups are too wide to fit the channels in the pinion.... weird right? Am I missing a crutial step, should I be putting the c clips in after the joint is in and the straps are bolted up? Can I install without the c clips, bolt the retainers, install one c clip, then gently tap the other side until I can install the second? Cant find any videos or step by step instructions. Any help would be appreciated.
 
Sometimes when pressing the caps in, you inadvertently will press the ears of the shaft together so that it's hard to get both C clips in. Most of the time a swift rap with a hammer in a spreading motion of the ears will solve the problem.
 
Definitely don't want to install the caps / retainers without the clips ... if you do make sure there's no one standing beside the car when you start to spin the driveshaft. Here's a link to a u-joint girdle that might just help you ...

U-Joint Girdles
 
Also sometimes there's too much grease / air in the cross itself ... remove the grease fitting if it has one & maybe you will be able to squeeze the caps in further.
 
It's not the ears on the propeller/drive shaft, its the ears on the pinion. We're talking like 1/32"-1/64" to get the retainer clip in. I checked inside the cup, all the needle bearings were sitting right, there wasn't too much grease, I have the grease-able kind of u joint.
 
roylerumble said:
It's not the ears on the propeller/drive shaft, its the ears on the pinion. We're talking like 1/32"-1/64" to get the retainer clip in. I checked inside the cup, all the needle bearings were sitting right, there wasn't too much grease, I have the grease-able kind of u joint.
Click to expand...
Then it may be a poor quality u-joint. What brand is it?
 
On the pinion yoke the caps should be captured by tabs or machining on the yoke itself, and then the straps go on.
 
GeorgeH said:
On the pinion yoke the caps should be captured by tabs or machining on the yoke itself, and then the straps go on.
Click to expand...

Nope, There is a machined groove on the inside of the cap that the snap c ring clips on the cap and a machined edge on the inside of the pinion to keep it from shifting around. There is no way I can get both rings on and have it fit.... The napa part in Canada was UJ347 and the US part number is nuj240-0369

Any one help?

Please!
 
I have come across that before.
I'm guessing the pinion has a 7290 joint saddle and the Driveshaft has a 7260.
If your 340 has clutch, you will want a proper driveshaft with 7290 joints.
But
I have found that the C-clips on the adapter joint are too thick . I had to transfer the originals from the old 7260,over.
You may be tempted to grind the crosspins shorter, and that may be a viable option; but cutting the same amount of each side will be tricky.

I think there are three different methods of locating those cups in the saddles. There is the type you seem to have; where the C-clips fit between the saddles. And then the type GeorgeH mentions, where the locators are on the saddles. And the third is a U-bolt type with the locators on the U-bolts themselves. I have only seen the first two types in Mopars after 1968.
 
Last edited:
roylerumble said:
Nope, There is a machined groove on the inside of the cap that the snap c ring clips on the cap and a machined edge on the inside of the pinion to keep it from shifting around. There is no way I can get both rings on and have it fit.... The napa part in Canada was UJ347 and the US part number is nuj240-0369

Any one help?

Please!
Click to expand...
I have also found some aftermarket clips too thick to fit correctly, & as mentioned some pinion yokes have retaining tabs & do not need the clips,
and may not be machined square to accept them.....................
 
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