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broken front universal-joint

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Greaser007 View Drop Down
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    Posted: 16 June 2019 at 1:03pm
Greaser007 here inputting some info on front axle u-joint Failure:

Not all of us here in the Forums are "seasoned-veterans" of 4-wheeling.

In my 18-summers of traveling the famous Rubicon Jeep trail, most summers I would take the wife or a friend or my dad with me, and we would go into the Rubicon trail one-day before the famous Jeeper's Jamboree, and set up camp at Spider Lake to watch 400 vehicles crawl through, or around the Little-Sluice-Box.

I guess a person could see 400 jeepers in one day at the Easter Jeep Safari too.

I think I saw everything from shocks ripped off of frames, power steering boxes ripped off of frames, over-turned jeeps, broken leaf springs, Pinion gears broken and snapped off in two.   Oh, and Broken U-Joints big time.
   There is a science to properly setting up steering and steering LOCKS or STEERING STOPS.
   In my opinion the radial movement of the Pitman arm should be the stop working in conjunction with the adjustable stops on the knuckle or housing.

   I have personally spoken with Parts Mike in Gardnerville, Nevada 20-years ago in our travels through Nevada. If you look at his website, he does have a Technical Section for helpful information. He discusses U-joint failure in front axles and touches briefly on Steering Stops. Oh, so you do have a Rock-Ram installed, and who installed it.   What stops the ram, and are your stops adjusted to prevent U-joint BIND ?

http://www.partsmike.com/index.php/content/4x4-support

    Sorry, but my jeeps are not set up to be "numbers-correct" as delivered from the factory.   I have always converted my jeeps to Cross-over Steering to have a hishway-friendly steering system.   The split wishbone tie-rod design was a good system for the Willys back in the '40's, but things have changed for the better over the decades, and I just don't care for the original design.

    Parts Mike sells flat-top knuckles and components to change or modify our steering from the split tie-rod and Bell-crank design to Cross-over.

   If the radial throw of your pitman arm esceeds the steering stops, you are then just pushing everything sideways and stressing hangers and such.

    Shortly after Jeep produced the Rubicon model, there were many front axle failures. Probably due to the owner installing Larger diameter tires and thus putting more stress on the smallish front axles and u-joints.

    One other thing I forgot to mention that may be of interest:
    How many of you have twisted front drivelines, but not broken them ?

    Here is my thoughts on this. I have twisted several front drivelines on the Rubicon trail.   ( I crawl underneath and check everything when I get home ) to see what may be close to failure.   On the granite and descending steep inclines, I think as the jeep rocks fore and aft, and dropping down off those steep stair-steps, the shock loads can twist a small diameter shaft tube.

    I watched the guy at the driveline shop lengthen and shorten my drivelines back in 1984 when I installed a Ford T-18 into my '77 CJ-7.   He put his torch to the driveshaft tube (to "straighten" it). I told him that he just took the temper out of that cold-roll tubing, and that it would now twist on the trail.
Sure enough it Did !    From then on, I explicitly requested No-Torch on the driveshaft tubing.    There is a science to all of this.
    And that is to Be Happy and enjoy the Willys.

    Make sure your steering geometry is correct and no Binding in and rod-ends or U-joints.   I took a grinder and clearanced all my u-joint Yokes to be sure there was no-binding on anything at full articulation before traversing that brutal Rubicon Jeep Trail.

    Sorry, I have trouble writing a brief thread.   :)

We could give a new name to clearanced U-joints "Duluth", no pinch, no bind.

Edited by Greaser007 - 19 June 2019 at 11:06am
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nofender View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nofender Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2019 at 5:57am
Agreed on steering angles and upgrades. 

One thing we used to do with our driveshafts - we used to paint a white line on them - the length of the tube. Then you could easily see the twist start. I found the twisting almost never happened the day of failure. But likely started on a prior trip. Anyway - easy visual to check if you got some twist going on. 

Also if you are getting shafts built or are building your own - specify .120 DOM tubing. Many shafts are made from .85 welded seam tubing. That slight upgrade makes all the difference in the world. Ruffstuff sells all sorts of DOM in short lengths, so you don't end up buying a long stick you don't need. 
46 CJ2A rockcrawler
46 CJ2A resto-mod
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SE Kansas 46 CJ-2A View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2019 at 9:53am
Keep in mind that a driveshaft is much easier to repair than a broken part in an axle. The driveshaft kind of acts as a "fuse" that can fail before that expensive locker diffy blows up and ruins the ring and pinion or a hard to find axle shaft. Most OEM driveshafts for CJ's were constructed from .095" DOM tubing.

I don't have any rock crawling experience to speak of but I have repaired driveshafts for a living. Many of my customers did rock crawling or mud-racing. While replacing a driveshaft isn't exactly cheap, I have cleaned up many messes in an axle housing for customers that involved some expensive parts. At least some of these were caused by "over-engineering" the driveshaft.

I do agree with Greaser that absolutely no torch heat be applied to a driveshaft. That is a no-no.

46 CJ-2A #64462 "Ol' Red"



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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greaser007 Quote  Post ReplyReply Direct Link To This Post Posted: 02 July 2019 at 12:13am
Nofender:
   I like that idea of the straight stripe to check the driveshaft.

SE Kansas:
   You have seen it all being in the business end of driveshaft repair.

   Just think how much fun the drivers were having before the drive lines and u-joints needed attention. :)
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