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Do I need a conversion U-Joint?

Chevy305

Chevy305

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My rear shaft u-joint at the pinion has some play in it again and not the usual play. The u joint can move back and forth in the yoke. I've been fighting this problem for a while now by just replacing the joint with one from an over the counter parts store. So the drivetrain truck was originally an '84 456/208 with a 10bolt rear and I swapping in a 14bsf. The u joint bolted right in so I just ran with it. Since then every few months to a year I'd have to replace it because of vibration and play. I've finally taken a harder look at it and I noticed that the u-joint itself is fine but it has play in the yoke. See here:

2014-09-17 17.07.46.jpg

So since the standard u-joints don't seem to fit width wise in the yoke I guess I need a conversion u joint right? Well doing some searching has netted me with the Napa 447 joint which is a SR4-1350 style. However, that part has one side external snap rings and one side internal. The problem is that I need external on both. See here:

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Universal-Joint-U-Joint-Combination-Universal/_/R-PUJ447_0010270151


And looking at the chart of u-joints on this website:

http://www.driveshaftspecialist.com/HTML%20Measure/UJ%20ID%20Guide.html

I don't see how I'd need any conversion joint with the measurements from that chart.

What the hell is going on here?

2014-09-17 17.07.46.jpg
 
The 14 bolt should have a 1350 u-joint, the 84 should have a 3R joint in the shaft but those are internal c-clips 100%. Measure up your driveshaft and figure out what it is, with external clips it's not 3R.
 
My 14sf takes a 1350.


You don't need external on the yoke side, you have extra room there because the joint is not wide enough for the caps to hit the yoke tabs.
 
Deuling said:
My 14sf takes a 1350.


You don't need external on the yoke side, you have extra room there because the joint is not wide enough for the caps to hit the yoke tabs.
Click to expand...


This^^^^^^^I just did my swap a couple weeks ago with the conversion joint, fit in there like it should. No external clips.
 
I had the same problem when I had a sf, even with a new u joint. turns out those little tabs wear out in the yoke. I bought a new one for about 80 bucks and the problem was fixed. The tab, if not warn out should have a chamfer to the inside. I never knew that was there in the first place but holding old yoke next to new yoke I can see the difference.
 
Deuling said:
My 14sf takes a 1350.


You don't need external on the yoke side, you have extra room there because the joint is not wide enough for the caps to hit the yoke tabs.
Click to expand...

So you are saying I can slam the SR4 internal clip part of the u-joint into the yoke and use the external 1350 side in the drive shaft yes?
 
38377k5 said:
The 14 bolt should have a 1350 u-joint, the 84 should have a 3R joint in the shaft but those are internal c-clips 100%. Measure up your driveshaft and figure out what it is, with external clips it's not 3R.
Click to expand...

The shaft is definitely a 1350 external clip style.

Could the play just be because the tabs on my yoke are worn?
 
Chevy305 said:
So you are saying I can slam the SR4 internal clip part of the u-joint into the yoke and use the external 1350 side in the drive shaft yes?
Click to expand...



If you get the conversion joint it would put the 1350 part in the yoke, and the smaller in the driveshaft.


I just got a 1350 driveshaft so I didn't need to deal with goofy joint.
 
I measured the tabs on my yoke and the u joint. I get 3.636" on the joint and 3.674" on the yoke. That's a 0.038" difference. Does that point to my yoke being worn out?
 
That gap looked way bigger than that to me, so possibly.


Somebody must have specs on the stock yoke dimensions.
 
Chevy305 said:
The shaft is definitely a 1350 external clip style.

Could the play just be because the tabs on my yoke are worn?
Click to expand...

Yes, if you continually have issues the wollowing around could have worn out the tolerances in your yoke, you may need a new yoke.
 
Chevy305 said:
I measured the tabs on my yoke and the u joint. I get 3.636" on the joint and 3.674" on the yoke. That's a 0.038" difference. Does that point to my yoke being worn out?
Click to expand...


Yes your yoke is warn out. There should be a gap range of thousandths, not 38 thousandths.
 
Glenn, if you get a 10 bolt yoke it bolts right on to the semi float 14 bolt. This is what I did and I can run a stock Blazer u joint and not worry about finding a unicorn of a u joint. Like i had to do when I threw it on the way home from Michigan last year :doah:
 
Well I ordered a new 1350 yoke for it and a Spicer u joint. But now typing this reminds me that I forgot to order a new seal for it...


I also ordered a new yoke and joint for the front 10bolt too as I found that one had the same play in the yoke. It also has play in the pinion bearings so I guess the whole front end needs to come apart too... [emoji36]
 
Chevy305 said:
Well I ordered a new 1350 yoke for it and a Spicer u joint. But now typing this reminds me that I forgot to order a new seal for it...


I also ordered a new yoke and joint for the front 10bolt too as I found that one had the same play in the yoke. It also has play in the pinion bearings so I guess the whole front end needs to come apart too... [emoji36]
Click to expand...

Might as well.... :whistle::doah::haha:

:popcorn:
 
Pay to play my friend. Sorry bud.

Pinion bearings are not bad though. Is the but tight? If they come loose you will have slop.
 
Deuling said:
Pay to play my friend. Sorry bud.

Pinion bearings are not bad though. Is the but tight? If they come loose you will have slop.
Click to expand...
I need to replace the inner axle seals on it anyway so I "might as well" do it right and check both bearings and replace the crush sleeve.

I'm just frustrated that I have to spend time and money fixing something stupid like this. [emoji36]
 
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