Found a correct 63 rear spring - now what?

[Harry S.]

Re: Found a correct 63 rear spring - now what?

If you order the liners from Quanta, ensure you tell them that the liners are for a 63 spring. The difference being on a 63 spring the first and second leaves do not have a liner between them. In the 64 to 67 sring there is no liner between the third and the fourth leaf. The liners from Quanta looked identical to me.

There are several pictures of 63 springs in the archives, If you can't find them let me know and I'll post a few.

[Jeff A.]

Re: Found a correct 63 rear spring - now what?

I measured and I only got 9.5"
How bad would that be - only 1/2" from spec?

It cleaned up real nice with just a hose...
The rubber is soft, it has never been painted, and I could really just bolt it right on.
This car needs a new rear spring - bet this is better then the one I have now.

BUT - Is this acceptable as it is, without re-arching?
This car is just a few notches up from a daily driver.

[John D.]

Re: Found a correct 63 rear spring - now what?

Jeff, Even though your car is just a driver as you stated here is my approach. When you are working on a particular part on the car restore it to the best of your ability so you don't have to go back later and do the job over again which results in added expense and down time.
63 springs were not painted. As mentioned the two top plies did not have a spring liner. We used Quanta Pre lube on the spring for my 63. Buy a new center bolt, some liners and do the spring up correctly. You won't be sorry. John

[Jeff A.]

Re: Found a correct 63 rear spring - now what?

Thanks John for the reply.
Do you think that doing those things will put the spring closer to the factory spec,
or will I still need to have the spring re-arched?

Or, should I use parts of this spring as a donor for a new Eaton?

[John D.]

Re: Found a correct 63 rear spring - now what?

Getting a spring re arched appears to be a dying art. If you can find a shop that does it get it done. Better than using a replacement spring. John

[Jeff A.]

Re: Found a correct 63 rear spring - now what?

But is it worth doing a re-arch for only 1/2"?
Probably not.

Will try to tackle this one soon.

[John D.]

Re: Found a correct 63 rear spring - now what?

Jeff, I am not qualified enough to answer your question on the spring sag. John

[Jeff A.]

Re: Found a correct 63 rear spring - now what?

Think I am going to disassemble and inspect it.
then decide -

I would really like to use it as is if I can.

The last time I did a rear spring...
I had to replace the fronts, to equalize the ride height.
At this point my front springs are just fine thank you.
An used spring may be exactly what I need.

[Duke W.]

Re: Found a correct 63 rear spring - now what?

So, measure the arch and compare to spec to determine if it needs to be re-arched...

Don't know how to measure free arch? Lay the spring flat on its side. Draw a chord though the center of the end holes. Measure from the center of the chord to the bottom of the spring above.

Factory spec is free arch = 10.0"

Do you have a tolerance for this dimension?

Consider that in the relaxed state it would not take much force to compress the spring to 9.5". What really counts is whether the spring has sufficient force when defected to the normal ride height range. The AMA specs have this specification for all springs, but it would take a proper test fixture to actually test the spring.

There have been numerous discussions about "spring sag". Based on my understanding of the material properties of properly heated "spring steels", normal operation will never result in "sag" because steel has very low creep characteristics.

The two primary causes of sag are overloading and corrosion. Overloading can stress the steel to the yield point, which can result in permanent deformation, and corrosion can reduce material mass to the point where the spring's deflection-force characteristics are significantly degraded.

Another frequently overlooked issue is that most "spring sag" is caused by old, compressed spring link cushions, and in most cases, new cushions will restore normal ride height.

All too often OE springs are discarded for no good reason, and if the spring has no significant loss of material from corrosion, a cleanup, new liners and new spring link cushions should return it to as-new performance.

IMO "rearching" has ruined more good springs than returned damaged springs to original performance.

Duke

[Jack H.]

Re: Found a correct 63 rear spring - now what?

No, I don't have the tolerance, Duke. Noland Adams' Vol 2 book cites rear suspension specs in the Specifications appendix. But, unlike his front suspension spec section, there is no definition for either free height or working height...

My book has been annotated with the rear spring free height specs and today I can't remember where I got the data from. Could have been from prior conversations with Noland (a good guy) or from a suspension shop's spec book...

[Duke W.]

Re: Found a correct 63 rear spring - now what?

From the '63 AMA specs the rear spring load is 1360 pounds at design (full load) height at -0.352 camber, and the rate is 162 lbs/in. Length and width of 4.36" by 2.25" is specified, and my notes indicate SAE 5160 steel.

The only thing I found in Noland's Vol. 2 (page 450) is length and width of the spring.

I consider "free arch" length to be purely anecdotal and would give it a fairly broad tolerance and not depend on it as go/no-go use criterion on a spring that otherwise shows no evidence of damage or significant corrosion.

Duke

[Jack H.]

Re: Found a correct 63 rear spring - now what?

"The last time I did a rear spring... I had to replace the fronts, to equalize the ride height. At this point my front springs are just fine thank you."

Knowing if your front spring(s) are OK, is simple! Pull out your copy of Noland Adams' Vol 2 restoration book and dive to the back where the Specification section is.

You'll find specs for both the Front and Rear Suspension for mid-year cars. The Front Suspension has solid details on the springs including both their Free Height and Working Height.

These are the 'goodie' tidbits that are missing from the Rear Suspension section... Noland only gives us factory specs on the length and width of the rear spring.

[Duke W.]

Re: Found a correct 63 rear spring - now what?

The specs in Noland's book come from the AMA specs, which are available at no charge to vintage Corvette owners - as long as the program - or GM - are still around.

Duke

[Jeff A.]

Re: Found a correct 63 rear spring - now what?

Installed the spring last night.
I replaced the liners, and cushions, as well as the center bolt, and cotter pins.

Very happy - the ride height is right back to perfect, and the car drives just great.

Cleaned each leaf with a wire wheel, then after assembly -
I used low gloss clear on the exposed surfaces - for a natural metal appearance.

Big difference in the way the car corners too.

[Gary B.]

Tolerance is +/- 0.125"

According to my notes which I got from some GM source some years ago, the tolerance is +/- 0.125."

Gary