Premature U-Joint Failure < 2000 miles!!!

[Ludigdrums]

Hey all...well, I was very excited today because I finally got new coil springs and smart struts from VBP to get my baby back up an running. What happened was, when I put on new wheels and tires (18x10) the suspension was all sitting way too high. I chopped some coils off the front springs and went from 8" to 10" bolts in the rear. It sat nice, but couldn't be aligned because of too much neg camber in the rear. So, I haven't been driving it and have been waiting for the right $$$ priorities to go to the Vette. I decided to go with the 550lb front coils and they sit nice and not too low as before. Then I went to put on the smart struts and found a problem...

My U-Joints are all busted. They are < 2000 miles old and installed at the end of April along with complete offset trailing arm assemblies, rotor, etc. I had the half shafts reconditioned here on LI (Corvettes Unlimited, NY), and they pressed in new U-Joints.

I can see that the cups look like they're cracked and broken...there is a lot of play at the rear wheels. I'm really hoping this doesn't affect my new assemblies runout and everything.

How can this happen?!?! I've only driven 200 miles since I lowered it and threw the alignment out of wack. But how could that mess all of the joints up so quickly!?

Sorry so long...I'm so dissapointed because I just want to be able to drive my baby. I just bought a house this summer, so $$$ been tight and that's why I've waited to get the parts I needed and haven't driven ALL summer long. :-(

Thanks!

- Jeremy

 

[norvalwilhelm]

U joints don't all go at once and certainly not in 2000 miles. Perhaps they were installed wrong? Pressed in too tight distorts them causing they to prematurely fail. It is not the end of the world, joints are cheap and easy to replace if done right.
I remove the old joints with a cutting torch. I burn the cross out of the center, then use a air chissel to knock the cups out, a flapper wheel or emery paper to really polish the yoke bores, debur with a file, clean the groove then hold the shaft in the vise and using a small brass hammer, lots a oil walk the new caps in with light tapping.
This way the yokes don't get bent, deformed because no press was used.
I don't believe in tight press fits. The cap is deformed causing the bearings to run tight then loose causing premature failure.
Good luck

 

[Ludigdrums]

Hmmm, they looked great when I got them back from the shop. They pressed them in. I'm hoping they will warranty them if I take them back out and show them.

I'm still really confused how this could have happened though. The staps holding the caps on are nice and tight. I could understand maybe if they were loose...but they're not!

Thanks again!

- Jeremy

 

[JohnZ]

How "jacked-up" is your rear suspension to clear your tires? If the angles on your half-shafts are much more than shown in the photo below (stock '67), the U-joints are running beyond their design operating angle limits and they'll get eaten up in a hurry.

 

[Ludigdrums]

Thanks for the pic.

Actually, the rear wasn't jacked up, it was lowered in order to decrease the enormous space inbetween the wheel and the well. The half shafts were almost horizontal, but with a little angle downward like in your pic. From what I have read, that is what you want, for them to be close to horizontal but not quite.

So, again, this is why I'm confused...remember, everything is new back there (complete offset trailing arm assemblies from Van Steel). I don't get it.

- Jeremy

 

[mike weyman]

a real sloppy machanic with an affinity for dropping things shaped like "pins"and not looking for them?? 1 pin out of place = quick failure.mike

 

[wallyknoch]

U joints don't all go at once and certainly not in 2000 miles. Perhaps they were installed wrong? Pressed in too tight distorts them causing they to prematurely fail. It is not the end of the world, joints are cheap and easy to replace if done right.
I remove the old joints with a cutting torch. I burn the cross out of the center, then use a air chissel to knock the cups out, a flapper wheel or emery paper to really polish the yoke bores, debur with a file, clean the groove then hold the shaft in the vise and using a small brass hammer, lots a oil walk the new caps in with light tapping.
This way the yokes don't get bent, deformed because no press was used.
I don't believe in tight press fits. The cap is deformed causing the bearings to run tight then loose causing premature failure.
Good luck

Perfect example of the correct way to remove and install U joints.

 

[lone73]

u-joints

Hey Jeremy,

I have my share of troubles with u-joints in the past as well. I learned a little bit that I could pass along. The last time i had it done I had a shop press them out and in. The guy wasn't too meticulous and ended up bending the outer flange thing slightly u-shaped - thats the piece that connects the half shaft to the inside of the hub (I don't know what you call it). This thing should flop around easily when you get the shafts back from getting new joints. There should be no resistance in either direction of movement. Mine were really binding in one direction due to the bend he induced. One is still ok. I just replaced the right outer side again after only about 8K miles.
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[norvalwilhelm]

When doing the outer flange , if you insist on the press method requires a support be bolted to the flange before pressing to prevent bending.
The first time I made a holder to bolt this flange too but now I just use the cut method.