u-joint failures

[72 fastback]

I have a 1972 mustang fastang with a 4 speed. I was breaking u-joints every time the car wheel hop badly. The needle bearing were getting wasted due to the fact that the u-joint was getting chewed up and no longer round. This was happening only at the caps that go in to rear yoke. I have discovered I only had a 1 degree positive pinion angle. I then installed a 2 degree wedge and it seemed to make a major difference. My pinion angle is between 4 and 5 degree. I also installed traction bars. If I drive car extremely hard it will still damage u-joints. Burnouts and mild powershifting don't seem to effect on short term. Also get high speed vibrations, which I bielieve is due to wimpy trans mount. Any help would be greatly appreciated. Is there any manufacture that makes a polyurathane trans mount for a stick car. It has to mount to trans in center like the origanal.

 

[12sec67]

did you have the vibration before installing the wedge because it could be due to that.
i think i heard differently..you should have a negative degree pinion angle (-2 or -3) not the other way around.

energy suspension makes polyurathene trans mounts.

 

[72 fastback]

I may be mixed up with the positive or negative pinion angle. My drive shaft was almost in a straight line before installing wedge. Now it is around 4 dergress pointing down.

 

[72 fastback]

There doesn't seem to be an appliction for my car from energy suspension 72 mustang trans mount

 

[thehueypilot]

My car was eating rear u-joints until I figured out that I had the wrong u-joint installed for the pinion yoke I was running. It looked close but was the wrong one. I showed it to a driveshaft builder and he thought the yoke was worn but after sleeping on it he found out it was the wrong u-joint for that yoke which caused it to walk around just enough to put it in a bind and destroy in very short order. It was an 8" rear end and the yoke came from Currie enterprises which puts these unusual yokes in there third members, but the correct u-joint was found and problem solved.

 

[72 fastback]

thanks thehuey pilot my third member has a small yoke on it that takes a 1 1/16 cap and it it a 9" rear there may be something there. I thuoght mine was wore out too. But if i slide my rear backward and hold presuure it doesn,t seem to walk.That is before I tighten U bolts.

 

[72 fastback]

That is if I slide drives shaft back towards rear. Even if I tighten u bolts a little it doesn't seem to move. but it might under heavy loads. thanks again.

 

[MitchGT]

Are you tightening the u-bolts to spec? Maybe overtightening is distorting the caps?

 

[davishokies]

What is the symtoms of worn u-joints? Do they make a noise? I've replaced (rebuilt 8" on 68 Coupe) my third member about 3000 miles ago because it was whining. I now have a low pitch wa..wa..wa at low speeds. Didn't mean to hijack the thread, but any info would be appreicated.

 

[72 fastback]

Hey mitchgt do you know the torque specs by any chance.