72 Riviera rear u-joint

**oilytinman** · 09-09-2012, 05:50 AM

72 Riviera has drive shaft noise and vibration. I have replaced both rear joints but not the ball. Could this be the cause? Anyone have experience with this?

**bob k. mando** · 09-09-2012, 07:10 AM

that's a special joint called a "Constant Velocity" or CV joint. there should be CV joints at both the front and back of the driveshaft.

more relevant to your problem, i think the early 70s big cars have a two piece drive shaft. the pieces are joined by rubber. if the rubber has deteriorated ( and it probably has ), it's not going to be possible to balance the drive shaft until you either get that reconditioned or if you replace it with a one piece shaft.

**oilytinman** · 09-09-2012, 03:55 PM

Originally Posted by bob k. mando

that's a special joint called a "Constant Velocity" or CV joint. there should be CV joints at both the front and back of the driveshaft.

more relevant to your problem, i think the early 70s big cars have a two piece drive shaft. the pieces are joined by rubber. if the rubber has deteriorated ( and it probably has ), it's not going to be possible to balance the drive shaft until you either get that reconditioned or if you replace it with a one piece shaft.

This particular shaft has a single u-joint behind the transmission but a double (cv) at the differential where the ball component resides. Don't recall any rubber sections. Appreciate your response.

**raycow** · 09-09-2012, 06:52 PM

You don't have to worry about any rubber parts. Those are used only on cars that have a two-piece driveshaft.

Shift the transmission to neutral to make sure there is no load on the shaft. Now grab the yoke just behind the transmission and try to wiggle it up, down and sideways. If don't feel any play, grab the yoke in one hand and the shaft in the other. Again, you are trying to feel for play between the two parts.

If no play in the front U-joint, you will have to take the rear U-joints apart so you can inspect the ball and ball seat for damage. A seat replacement kit is available, but if the ball is bad, I don't know if that part is still being reproduced.

Good luck, and please let us know what you find out.

Ray

**oilytinman** · 09-29-2012, 11:48 AM

I purchased a constant velocity kit from Cars Inc. and installed most of the components. The ball did not fit and it appeared the existing ball was pressed or threaded to the center component. That cured the vibration. Thanks for the posts, hope this might help someone else. Bob Summers

**sabrerattler7** · 11-24-2012, 01:55 AM

I had a CV in which the ball froze and snapped off. That results in horrible noise and major vibration. Because the 2 piece rear shaft vulcanizing had broken loose as well (68 Riviera) the CV joints (front and rear) were out of registration and that will cause major vibration, the shop created a new solid shaft and used a K5 Blazer CV to create a new rear assembly.
By the way you really can't see the vulcanizing rubber as the shaft is made up of 2 different size tubes slipped inside each other with a gap in size filled with hot rubber. Idea was to isolate shocks from the differential and rear CV vibration from the rest of drive line.
Problems showed up when they get old and we hot rodders add power up front and big rubber in the rear that breaks the rubber bond and twists the CV's out of alignment.