I have a '63 in good shape and correct. Driving down the road at a lazy 35 mph, another car started to run a stop sign. I hit my brakes hard, and then the gas again as the other car stopped. I immediately knew I had a significant problem. The universal joint, closest to the rear end, on my drivers side half shaft, was destroyed. I ordered a new half shaft, complete with universals, while rebuilding the original. I checked to insure the rear wheel bearing was spinning freely and true. I did the same check for the shaft and universal coupler exiting the rear end. Luckily there was no other obvious damage. Once I replace the half shaft, with new universals, I checked the wheel rotation, while the car was still on the lift. As I rotated the wheel, that was hanging freely, the drivers side will spin, almost 360 degrees, and then bind. I can see the universal just outside the rear end at a very acute angle when the wheel binds. Meanwhile, the passenger side wheel spins freely. I loosened and re-tightened the universal bolts multiple times, insuring they are tightened evenly. The one thing I did notice is that the drivers side rear spring hangs 1.25" lower than the passenger side, measured from the frame. When I raise only the left rear wheel, in relationship to the rest of the car, just 3/4", it spins without an issue. So it appears the trailing control arm can travel further. This seems to create a more acute angle at the universal, just outside the rear end. So the drivers side wheel, and associated suspension, seems to be able to range lower, in an event when the nose of the car dives and the rear end is forced to lift. The rear spring only has 28,000 miles on it, and appears to be in good shape. Do any of you mechanical gurus have any suggestions? Am I even on the right track? What else could be causing the universal to bind to the point of self destructing? Any suggestions or similar experiences would be greatly appreciated. Thank you and Happy Holidays.

 

Any chance you could post a picture of the rear end from wheel to wheel with the tires off the ground? It would help to see what the suspension components look like with the weight off the tires.

 

I think your problem may be due to the amount of shock absorber travel on the suspension. As I'm recalling, the original shock absorbers limited the amount of travel downward for the rear wheels and prevented them from travelling so far as to put the universals in a bind. If you or someone has replaced the shock and it provides more travel than the original, it may not be limiting the wheel to the same amount of travel as the original. I've seen several C2's on a lift the with the rear wheels hanging loose, and rotation is limited by binding of the universal joints.

As long as there's no binding when the car is on the road, and you're not flying over the hills with the wheels leaving the road, I wouldn't worry about it. As Avispa says above, a picture would likely help with diagnosing the problem.

Ron

 

Having just over-hauled my 63 rear end the above makes sense, at some point, somebody here posted the max travel for original shocks and yes, aftermarket shocks allowed more travel.. When tightening my 63 U joints bolts during the rebuild there was a distinctive klunk-klumk while turning the wheel SLOWLY to get access to the bolts, but not a complete bind. The three link suspension is the T/A arms, strut rods and U-joints for up/down and sideways independent movement and the leaf spring for vertical movement. I think you may be OK as your car should never see such an extreme amount of travel on the road. Your leaf spring cushions may account for the leaf spring disparity in the distance you measured on each end perhaps.

Over travel due to modern shocks is also why you shouldn't run a car with the rear suspended in the air with the wheels at full extension.

 

I'll work toward getting it back in the air again. We're in the midst of a fairly good size snow storm today, but I should be able to get a few photos in the next day or two. Thanks for the reply.

 

Thank you Ron. I had the same Delco shocks on the car for the last 14,000 miles, with no issues. That said, the original shock could have started to weaken to the point where the wheel was allowed to travel more than it should. I did replace the shock when the universal went, mainly because the half shaft dented it when the universal let go. As I mentioned to Avispa, I'll try to get a photo up ASAP. The confusing part to me is, after fixing the universal and replacing the shock, the left side binds, while the right side spins freely. It is good to hear that someone else has seen an example of the wheels binding when the car is off the ground. And even though I enjoy driving my Vette the way it was meant to be driven, I try not to go airborne, especially on those tight turns!

 

Thanks Frankie. I did see that as I raised the drivers side wheel, in relationship to the rest of the rear end, it went from a bind, to a klunking, to free wheeling, over the course of 3/4" vertical movement. By the way, when I say it binds, that's based upon my ability to turn the tire and wheel by hand. I haven't tried putting the car in gear and running it with both wheels completely off the floor. I'm not a mechanical engineer, but it seems to me, nothing good will come from doing that.

 

Maximum rear shock (mounting points) fully extended center to center dimension is 14-1/4 inches. If more than this, issues will arise.

Larry

 

I have my chasis bare during a body off, & the u joints bind without the weight of body on there. If I compress the suspension a bit & it rolls freely. It was concerning when I first noticed it, but thats all it was, the angle is greater than the car would ever see in real world conditions.

 

Right answer.

 

63 Vette Rear End Off The Floor, Suspension Hanging. My Apologies for the delay.
AVISPA and Ron, I hope this photo helps. I believe you may be able to see how the driver's spring end sits lower than the passenger side.
Powershift, it measurement is 15 1/4" on the driver's side, 14" on the passenger side.
Rob, if the wheel can't extend far enough to cause the bind during normal driving, then I must have another issue that would cause the differential to self destruct.

 

Could you have a worn (egged out) upper shock mount hole on one side of the frame as another poster on here recently found on his car ??

Unless its an optical illusion something is going on there, the DS lower leaf spring rubber cushion is much more compressed than the PS cushion....
Also the DS link also has less threads showing under the cushion at the cotter pin than the PS side, they should be very close to even...

 

I think the key to your binding problem in the air is primarily due to the overtravel allowed by the shocks as mentioned in my initial post. If you wish, try disconnecting one end or removing one or both shocks and see what the full extension of one or preferably both shocks have. As pointed out by Powershift, anything more than the 14 1/4" allowed by the originals will cause issues when extended past that amount.

Frankie's points are valid as well, but I don't think any of these would account for the total 1 1/4" difference between left and right sides you measure. You mention you replace the one shock after installing the rebuilt half shaft on that side. My bet is that you now have shocks with different amounts of extension on each side. I know you likely replaced the damaged shock with the "same" as originally installed, but I'd still suspect they're not the "same" even though they may be from the same manufacturer and be the "same" make/model. Only by checking the maximum extension of each will you know for certain.

That said, as has been previously mentioned, normal driving won't normally see the wheel being totally unloaded, which should be the only time it would be at full extension. So, from here you can determine how you wish to proceed . . . . . best I can advise you!



PS: Just curious . . . . what brand/model of shocks do you have on the car? Just wondering what the manufacturer's data might show, if any, for the extended length of the shock . . . .

 

I'm going through the same issue how about a 13 in shock in the rear?
What a poor design.
Any thoughts?
Thanks Doug

 

My 63 does the same thing with a QA-1 shock. Even more irritating the compressed dimension is too long so the shock bottoms before the rear hits the snubber. My car is low so I need a shorter shock or a dropped lower shock mount. Neither exists so i'm fabricating my own offset lower mounts.

 

Discovered the rear shocks are 14.750in. Looking into getting a pair of 14in.
Thanks for your input and incite new friends.
Doug