63 rear spring shifting / moving

[Henry A.]

Just finished the restoration of my 63 coupe...but need some help or suggestions as to why the spring leafs shift after driving the car...the leafs on the left shift forward forcing the right side ot shift towards the rear of the car. This typically happens to the second, third and fourth leafs from the bottom.

The rearend housing is a correct 63 part...the spring is an original (curled up ends), not certain if it 63 or not, it has been painted and new plastic dividers.

Any and all suggestion or insight will be helpful.

[Harry S.]

Re: 63 rear spring shifting / moving

Henry, let me guess and say that you replaced the bolts that hold the spring to the rear-end, am I correct??? If you did, then the new bolts are probably too long and you fortunately did not tighten them too much. This will cause the spring to move as you indicated. If you tighten them too much the spring will crack the rear end. I believe the correct spring length is 3 1/4 inches long. Check the length on the bolts. Also, double check what the correct length is.

If you have the correct length bolts, put the car on the lift, align everything and just snug up the bolts. Lower the car to the ground to settle the weight of the car on the spring. Then do the final tightening with all for wheels on the ground. Take a test ride and see what happens, it should be OK.

Do you have a picture of the spring, out of the car, to post?

Harry

[Henry A.]

Re: 63 rear spring shifting / moving

Harry, thanks for your reply. The bolts are new...not sure of the length. I will check them tomorrow. I am assuming that the correct length of the bolts is 3 1/4 inches...your post indicated the length of the spring is 3 1/4 inches. Thanks for your help. And yes we are concerned about breaking an ear off the rear-end cover. Henry

[Joe L.]

Re: 63 rear spring shifting / moving

Harry, thanks for your reply. The bolts are new...not sure of the length. I will check them tomorrow. I am assuming that the correct length of the bolts is 3 1/4 inches...your post indicated the length of the spring is 3 1/4 inches. Thanks for your help. And yes we are concerned about breaking an ear off the rear-end cover. Henry

Henry-----


The original bolts were supposed to be 3-1/8" long. A few other things to check:

1) Make sure that the spring CENTER BOLT has not bottomed in the carrier cover. Most SERVICE bolts have too tall of a head and it will bottom in the recess in the cover. The head must be no more than about 3/16" tall. If it's more, grind it down;

2) Make sure that the spring was fully de-arched before you torque the 4 plate bolts to spec. If it's not, you won't achieve the required torque when the car is on the ground and the spring will be "loose".

[Timothy B.]

Re: 63 rear spring shifting / moving

You would think that vendors selling a kit with spring liners for corvette would grind that center bolt down given the damage it could do to a rear cover. That's why it's important to keep old parts for comparasion when forced to use reproduction parts.

[Wayne M.]

Re: 63 rear spring shifting / moving

You would think that vendors selling a kit with spring liners for corvette would grind that center bolt down given the damage it could do to a rear cover. That's why it's important to keep old parts for comparasion when forced to use reproduction parts.

Timothy, others --- here's the orig. rear spring center bolt from my late '65. Just measured it and is exactly 0.50" head diameter and 0.25" head thickness. Has a "W" headmark.

Didn't measure corresponding countersink in rear cover, but it has to be close for locating purposes.

[Henry A.]

Re: 63 rear spring shifting / moving

Thanks Guys...I really appreciate your help. You have given me some things to check. This hopefully will solve my problem. Thanks. Henry