Rear AMC 20 yoke ujoint using Ubolts

wm69

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#1
Bought a set of Widetracs with Lockrights in both ends and one piece axles already installed in the rear.

Have them more or less installed but when I went to reattach the rear driveshaft, I discoverd the straps didn't work.

No problem, prior owner obviously coverted them to Ubolts, so i googled and found I need HELP! part number 81004.

Get them in, and the legs on the Ubolt are too wide. Tried squeezing them in a vice, and then the legs are no longer parallel so bottom line, they're too wide.

Figured I go the wrong part number, so went off to google again, ordered Spicer 2-94-58X. Same exact problem. Yes, I'm stupid for not cross referencing part numbers before ordering again. Was ordering parts sitting in line at the movie theatre.

So looking at specs....

2-94-58X
Bolt Center-Center distance 1.590
http://www.northerndrivetrain.com/pr...-2-94-58X.html

2-94-28x
Bolt Center-Center distance 1.416
http://www.northerndrivetrain.com/pr...-2-94-28X.html

That the diminsion I'm looking for, right? Wondering if the 28X will work. Going to go check it out and buy in person as opposed to chancing it again buying online.
 

AK-RWC

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#2
Maybe the PO drilled them and replaced the bolts with a nut/bolt combo? Rather than a full-on u-bolt?
 

wm69

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#3
Maybe the PO drilled them and replaced the bolts with a nut/bolt combo? Rather than a full-on u-bolt?
I guess that could work. He said he kinda remembered it using ubolts though. I had the axles for a couple years before I decided to put them in.
 

jims chop shop

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#4
Maybe the PO drilled them and replaced the bolts with a nut/bolt combo? Rather than a full-on u-bolt?
I did that on my build, and I have to look through my thread to find out the correct U-boats
I'm pretty sure I posted that in Jim's repair ration thread


 

jims chop shop

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#5
I can't find it, I posted pictures of the box somewhere at sometime with the part number
I'll keep looking


Sent from my iPad
 

bigwalton

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#8
I heard issues of people over tightening the U-bolt and messing up the U joint
That's a definite concern, impossible to over tighten the strap to distort the cap, but you can definitely do it with U-bolts. It's a choice over potentially loose strap bolts or potentially over tight U-bolts. Always wondered why they don't build in more of a shoulder/stop on the u-bolts so you have the best of both.

A number of years back I got a behind-the-scenes tour at Richard Childress Racing and got to crawl around a car they were prepping for a race. I was surprised to see that the axle yoke used straps and possibly crushing the caps was the reason they gave when I asked about it. Force on the cap is set by the design of the yoke, not the torque on the nuts.

I swapped the yoke on my HD20 when I went to U-bolts. As mentioned in the thread Jim linked, drilling out the strap holes weakens the yoke and the u-bolt yoke had longer "ears" to go around the cap than the stock strap yoke. Essentially, I consider the yoke and either the straps or U-bolts a matched pair.

Nice thing is that it's not a ton of $$ and you can throw your straps/bolts/yoke in the trail box as your spare. :shrug:
 

jims chop shop

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#9
Be careful changing the yolk out it's self, AMC 20s have a crush sleeve
You don't just re- torque it
( I think )

 

spankrjs

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#10
That's a definite concern, impossible to over tighten the strap to distort the cap, but you can definitely do it with U-bolts. It's a choice over potentially loose strap bolts or potentially over tight U-bolts. Always wondered why they don't build in more of a shoulder/stop on the u-bolts so you have the best of both.

A number of years back I got a behind-the-scenes tour at Richard Childress Racing and got to crawl around a car they were prepping for a race. I was surprised to see that the axle yoke used straps and possibly crushing the caps was the reason they gave when I asked about it. Force on the cap is set by the design of the yoke, not the torque on the nuts.

I swapped the yoke on my HD20 when I went to U-bolts. As mentioned in the thread Jim linked, drilling out the strap holes weakens the yoke and the u-bolt yoke had longer "ears" to go around the cap than the stock strap yoke. Essentially, I consider the yoke and either the straps or U-bolts a matched pair.

Nice thing is that it's not a ton of $$ and you can throw your straps/bolts/yoke in the trail box as your spare. :shrug:
Our local driveshaft/axle builder prefers the straps over the u-bolts, too. He uses strap type yokes on his race cars. I have never had a problem with the strap style, but I also would only run Spicer straps/bolts. Especially the little bolts, they are much stronger then off the shelf stuff:thumbsup:

Be careful changing the yolk out it's self, AMC 20s have a crush sleeve
You don't just re- torque it
( I think )
This too:thumbsup:
 

wm69

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#13

wm69

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#15
You may also think about a girdle rather than u-bolt... super strong and you don't have to worry about over-tightening/crushing the cap. Don't think the link I got mine from is any good now but you can find other suppliers if you search a little.
http://www.cj-8.com/forum/showthread.php?39916-U-Joint-Girdle&highlight=girdle
To wrap this one up, I took a piece of paper and poked holes to match the holes in the yoke, too it to my local FNAPS and ended up with HELP! 81002.

Looks like it's a GM part for the most part. Don't know if he drilled the factory yoke or if it's an aftermarket yoke, but these fit perfectly.

Just gotta bleed the brakes now and she'll be back on the road!
 
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