U-joints Shack rattle and roll

[68sunlitgold]

I started to feel a vibration in my coupe early this week. As the week went by it got worse. I initially thought it was a wheel or the engine but I started to rule that out doing different tests. I narrowed it down to the U-joints or the rear axle, figuring replacing both front and rear U-joints would be the easiest and cheapest fix I did that first. Once I took off the U-bolts and lowered the drive shaft, the two U-joint caps fell off along with a pile of dust. Attached is the picture of the U-joint itself and the end caps, the one on the right is what happens when a U-joint goes bad. After I replace both front and rear U-joints....vibration gone. I don't think they had ever been replaced (at least they had not since I owned the car which is going on 25 years). Glad I didn't find out what happens when one completely breaks down, but it was gettting close.

Doug

 

[davidathans]

ya i found out the hard way...twice...dropped driveshaft both times and would have dropped it a third time, i said hell with the 8" rear end and put in the 9"...made sure i had a -2degree pinion angle....no more problems

 

[joedls]

I was going through u-joints in my convertible. After about 3 u-joints, I decided to put in a stronger pinion yoke and support. The beefier pinion yoke did a much better job of taking the load off of the u-joint. I had to shorten my drive shaft when I did this. When I took it off, I found that the slip yoke was twisted. This was my problem the whole time. Too much torque just twisted it. It looked like a rifle barrell. I replaced it with a billet slip yoke and all is well in Denmark. :grin:

 

[PNewitt]

Hey Doug!

"Been There, Dust That"! Welcome to the "I dusted my bearings club".

Not only did I convert steel bearings to black dust on a U-joint, but I also did it to my rear axle bearings once.

Friction doesn't do well with ground up parts...LOL!

(...and to think I'm the only member of "I fried my C-4 over the Grapevine" Club!)

(Grapevine: Highway 5, up a 6% mountain grade from the San Joaquin Valley into north Los Angeles)

-Paul.

 

[case12]

What did the vibration feel like? I have been working to solve a vibration mystery on my 66 for some time. I had the drive shaft rebalanced, and surely the U joints were checked then. But the problem did not go away. What I feel is a vibration in the steering wheel and floor board that is somewhat fine, but periodic. What were you feeling? Casey