axle shaft u-joint replacement fail

[David F]

Well, I failed at replacing the stub axle end u-joint on one of my half-shafts.  I easily removed the original u-joint.  But, the Precision brand #393 did not cooperate. I suppose I used too much force pressing in the caps and bent the flange ears.  Should have used a spacer (to keep flange ears from bending) and probably measured the diameter of the caps on the replacement part.  Soooo, anyone have a junk half-shaft they are willing to get rid of cheap?  BTW, I have two complete axles coming from Ebay, but I want to rebuild my original shaft if I can.

Thanks.

Edited January 22, 2018 by David F

[Zed Head]

Are you sure it's actually bent?  They look bent from the shape of the casting but the holes are what matter.  You have to eyeball down the hole and/or use a straight edge to be sure.  And did you bend the inner yoke or the outer flange yoke?  Shipping on the half-shaft itself would be expensive.  Heavy.

[David F]

Not sure I bent it or not, but the retainer clip grove in the caps are not parallel to the surface of the ear.  And, the new u-joint is definitely in a bind which tells me the ears are bent.  Two used half-shafts on the way for $75 total.  I hope at least one has good u-joints.

[jonathanrussell]

I recently found out that they do bend with too much hydraulic press force. I just rebuilt a set of half shafts and found bent ears also. The result is abnormally tight c-clip installation and a u-joint that doesn't move freely. I am not sure whether I bent them or a prior owner. They had very thin c-clips and aftermarket u-joints so maybe the prior owner. I think it happens during removal of the old u-joints when seized...especially if a socket being used to press moves off of the joint and onto the ear.

Anyway, I have found that installation of the new joint is best done with a vice instead of a press. I used a dremel wire wheel attachment to clean the inside surface of the ear, greased lightly, and the u-joint caps press right in with a vice. I did damage one u-joint by allowing one of the needle bearings to dislodge and bend. Luckily I had a spare new joint.

[Captain Obvious]

I've done it. I bent the yoke pressing the U-joint caps out. Had to get a replacement yoke. This was many moons ago and the part was still available new from Datsun.

Memory is quite fuzzy, but I believe somewhere in a box around here somewhere... somewhere... There is a brace I made to prevent that from happening again. Strengthening spacer that fits between the ears. Once every couple years it turns up. One of those things you hold in your hand and ask yourself "What did I make this for again?"    

[David F]

I will chalk this one up to lesson learned.  If the used replacement half-shaft need new u-joints, I will definitely fabricate a support spacer from pipe or whatever.  The original u-joint pressed out seemingly as easy as any other I have replaced, but the new u-joint was a bear and I am sure I bent the yoke pressing in the new caps.  Ugh is all I have to say, but it won't be the last or most expensive screw-up I ever do while working on cars.  If you wrench as much as I do, it inevitably happens.  Just learn the lesson and move on.

[Captain Obvious]

Yeah, that's what I did as well. Chalked it up as a learning experience. And now that you mention it... I don't remember if I damaged mine taking the old caps out, or putting the new ones in. Vague fuzzy memory now seems to think I did the exact same thing you did and bent the ears putting the new ones in.

Cheap aftermarket parts with some fraction of a thousandth off is all it takes.

[Mark Maras]

 I too bent a drive shaft yoke some time back. Upon reassembly the clip wouldn't seat in the groove. Having nothing to lose I smacked the bent piece with a hammer until the clip would fit. Surprisingly, it worked. No vibration, even at high speeds.

[Zed Head]

3 hours ago, Captain Obvious said:

Cheap aftermarket parts with some fraction of a thousandth off is all it takes.

I rebuilt two half-shafts with $90 worth of Precision u-joints, four, from OReilly auto.  Then saw that they were looser than the old ones I had replaced.  So I removed them and took them all back for a refund.  I felt half-bad, but the parts really did seem of lower quality than the used ones I took out.

The Nissan joints have seven different thicknesses of retaining clip.  Probably why they cost ~$80 each  An old used Nissan joint is better than a new aftermarket joint, I think.  That's why I've stocked up on used half-shafts.

[David F]

Yep, Precision #393 from O'Reillys is what I tried to install.  The fit was definitely tighter than original.  Could have been due to me start them at an angle.  Seems like was pressing them straight, but who knows.   The original came out fine and I was only replacing it due to a slight notchy feel on center.  I think a bit of new grease and the new relative position of the bearing cap and the original would have been fine.  Again, lesson learned.  But, I did the same with the driveshaft and had zero issues.

I could probably fabricate a contraption that would allow me to open up the ears with my press, but at this point, $75 is the easiest solution.  If both shafts have bad u-joints, I will remove the original u-joints and replace with original.

All this happened because I am rebuilding the rear end (somewhat).  Isn't that the way it always happens...while I am at it, I might as well replace....  Anyway, new struts, strut isolators, rubber spacers, and bushings.  The spindle pin/bushes seem rock solid/tight, so decided not to worry about fighting the spindle pin.  What I found upon disassembly was a completely loose bushing end bolt (the large bolt that keeps the control arm from rotating in the bushing...probably the main source of the noise.

Last major project, getting close....

Edited January 23, 2018 by David F