Rear springs

[Harmon C.]

I have a rear springs that is off the car and three leafs are straight and the rest are curved. I think this is an original spring and may be a way to check them out at swap meets. I checked the spring on my 73 and when installed the gap between #3 and #4 leaf from the top is not there. I know their are other ways to tell original springs but is this a good sign?
As I recall their is no liner between 3 and 4.

[Harmon C.]

Re: Rear springs

30 hits and no one has a spring off a shark car laying around to tell me what it looks like unsprung. I have all the TIM&JG's but the information is limited to on the car original springs.

[Harry S.]

Re: Rear springs

Lyle, can't help with your spring as I have a 63. But, you are correct there is no liner between the last straight spring and the first curved spring.

On a 63 all the leaves are curved so there is a liner between every spring leaf. Always an exception.

[Terry M.]

Re: Rear springs

Maybe Gary Beaupre will look at this, although C3s are not his main interest. He wrote an article for The Restorer about C2 & C3 rear springs. I recall his mention of the straight leaves at the top, but I can't recall now what it means or what years it applies to. I do remember that the 1963 was different.

I think it has to do with whether the spring is a progressive spring or linear. That is the deflection per unit weight is the same across the spring's movement for a linear spring, but it takes increasingly greater weight to compress a progressive spring across its range of deflection. I hope I have that right, so as not to mess up the whole program. Maybe someone with access to The Restorer back issues can look this one up.

[Steve L.]

Re: Rear springs

Lyle,
I have my 73 original spring off the car but still attached to the diff. but unattched at the trailing arms. I took the entire rear off the frame as a single unit.

I can look at it this weekend as I've got other things I have to do in the next few days.

I can measure anything you want.

So far I gather you want to know where the liners are and whether the top springs are straight or tapered, is this correct?

This is definitly a 73 original factory spring unmolested so far.

Steve L
73 coupe since new

[Harmon C.]

Re: Rear springs

I doubt being attached to the differential will make a difference. The top three springs are straight an all the rest are curved.

[John H.]

Re: Rear springs

The photos below show a 9-leaf spring installed at ride height, and one in the free state; the one at ride height is a '65 and the one in its free state is a '64, but that 6-curved/3-flat configuration was the same from '64 through the late 70's.

[Harmon C.]

Re: Rear springs

Thanks John the pictures make it very easy to tell the configeration when in it's free state. Installed it is hard to tell the three are flat.

[Bob U.]

Re: Rear springs

I currently have the spring out of a 76 with Gymkhana Suspension and the top 2 are flat with the 3rd one very slightly bowed. There is nothing between the top two leafs or between the top plate and the top leaf. There are liners between the rest of them. This spring has seven leafs total.

[Gary S.]

Re: Rear springs

I have a spring just laying around here that I suspect is from my long gone 66. It looks just like the unsprung photo on the right in John's post. I can take a photo or two of it but John's is the same. The only difference was I removed the old worn out liners when I took it off.

Gary

[Daniel G.]

Re: Rear springs

I just removed the orginal (?) spring from my 63, 7 leafs and the top leafs are curved, I replaced with an after market 9 leaf and the top three leafs are straight.

[Harry S.]

Re: Rear springs

Daniel, save the 7 leaf spring. Is your car a Z06?

[Roberto L.]

Re: Rear springs

I have a rear springs that is off the car and three leafs are straight and the rest are curved. I think this is an original spring and may be a way to check them out at swap meets. I checked the spring on my 73 and when installed the gap between #3 and #4 leaf from the top is not there. I know their are other ways to tell original springs but is this a good sign?
As I recall their is no liner between 3 and 4.

Hello, this is my 70 coupe rear spring, a few years ago, out of the car after some work on it. 9 leaf type.

Best regards

[Harmon C.]

Re: Rear springs

Thank everyone for the help. All the other springs I had went to the scrap iron man for $130. a ton. Some had part numbers and most had the clamps around the leaves.

[Gary B.]

Rear springs; original GM vs. repro

Lyle,

I agree that with a two-stage spring installed in the car and fully loaded, it's hard to tell that the top 3 leaves are different from leaves 4-9 in terms of curvature. The best way to tell an original spring from a repro spring is to look at the shape of the upturned ends on leaves 2-9. But without a known original to compare with, it's hard to do that if you're never seen the real McCoy.

Gary