My '62 sits a little low on the stock and original rear leaf springs, GM #3751438. What's the common fix on this ? Are there resto. guys out there for the originals ? Or is it better to get some NOS or repro.springs ? Sources ? What is the R & R like on these springs ? Seems like a relatively simple project and I DID remove, detail and reinstall the axle/spring U-bolts and lower shock mount plate last winter, so those should easily remove now. I'm sure replacing leaf springs it has it's learning curve. Any helpful hints ?
"62 with tired rear springs
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Re: "62 with tired rear springs
Tom----
First off, C1s are not an area of expertise for me. However, I will offer these comments:
1) I don't know if your car requires new springs or not. It is my long-held opinion that leaf springs are a lot more durable and long lived than most folks think. My original owner 1969 still has it's original rear spring(twice rebuilt by me-not "rearched")and I am very satisfied with it in all respects.For my application, replacement of the spring liners and replacement of all rear chassis rubber bushings/cushions/mounts has always satisfactorily restored my suspension.
2) If you decide that your springs do need to be replaced, I doubt that you'll have any luck finding NOS examples to use as service replacements. Most othe GM chassis springs are "reproduced" under the "GM Restoration Parts Program" by Eaton Detroit Spring(www.eatonsprings.com). I have not been completely satisfied with their products in the past, but I believe that they have gotten better. In any event, they are probably about as correct of a spring that you are going to find in today's market.In Appreciation of John Hinckley- Top
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Re: "62 with tired rear springs
My experience is 50/50. Much depends on how tired the current springs are AND the experience of local who does your re-arch work. Some report having springs re-done by 'pro' shops only to see them again sag to condition they had before re-work within 5-10K miles of use. Others see top draw/robust results from rebuild effort.
You WILL find NOS service spare springs out there but be prepared to bend over on the cost and it would be ABSOLUTE serrendipity if what they had agreed with your car (originals have part number and date code on upper leaf that can NOT be seen when installed on the vehicle). My suggestion is to start making local phone calls to suspension shops in your area and get SEVERAL opinions regarding the specifics of your situation.- Top
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Re: "62 with tired rear springs
I tend to agree with Joe on this one. From a materials science standpoint there is no reason for a spring to sag assuming has not been overloaded, heated up to the annealing temperature, or significantly corroded. It's tough to overload a Corvette, and the annealing temperature of medium carbon spring steel is well beyond the melting point of fiberglass. Corrosion could certainly be an issue, but will vary from car to car. I think "spring sag" is more folklore than reality. Like Jack says you can expect quality to vary widely. Unless they have some dimensions to work with it's just guess work, and a lot of "processes" are involved with likely very little process control. The springs would have to be annealed, rearched, stress relieved, and then heat treated. The quality of the final result would like vary across a broad spectrum. A few years ago I looked around for a shop to make some anti-roll bars, but I never found one that I thought could or would do the job right, and they wouldn't guarantee anything.
My parts book does not show spring liners for your car, but if the shackle bushings are the same parts installed by St.Louis 38 years ago, then it's probably time for renewal. This could certainly be part, if not all of the problem.
Duke- Top
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Re: "62 with tired rear springs
Tom, I stand in line with those who suggest rearching your original springs. No rocket science to doing it, just have to find a spring shop who really knows what they are doing. I would suggest that you supply the "correct" spring liners to the spring people. In researching spring liners and if I understand it correctly, each of the original spring liners had four little steel "buttons" inside the cloth liner in the area of the spring plate. Three liners equal .300 height increase to the body to ground relationship. Today, most springs are relined with sheet plastic inserts and you will loose most of the height increase that you would have received from original style liners. Regards,- Top
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I've tried re-arching
Solid axle cars do sometimes suffer from spring "sag". I don't think this is caused by fatigue from flexing. I think it's caused by inelastic deformation during hard acceleration. I mean really hard acceleration - like dumping the clutch at 4,000 rpm.
The springs can actually be forced into an "S" shape when the axle housing twists. This is especially true for the pre-'59 cars without factory traction bars. They have a severe axle hop problem that you have to experience to believe.
Re-arching can return the ride height to stock, but it is a trial and error process. You'll probably find that the guy doing the spring repair is more like a blacksmith than a spring design engineer. Just be polite and patient, and eventually you'll get the ride height you want.- Top
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Re: "62 with tired rear springs
OK, so the concensus seems to be to remove the springs, get a good spring liner kit have a good shop rebuild the springs with the new liners and reinstall the springs with the new shackle bushings ( mine are absolutely original shacklebushings), Since the springs have only light to moderate pocking from good old west coast ocean breezes,they probably are fine as far as the "spring sag" issue goes. Am I on the right track here? Now.....any tricks to the removal and replacement ? And any good sources for correct liners ?- Top
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Springs....the rest of the story
OK, maybe this will help. This lowering of the car seems to be pretty recent. A few weeks ago, I was playing around with the car in a BIG warehouse and I tried my first ever big time burn out on the slick concrete floor. (Very fresh and strong 327/340HP with the dinky bias ply show tires on) I didn't prerev. the engine, I just slipped the clutch a tiny bit and jumped on the gas. As The tires slipped and the revs came up, I had this incredible axel hop that sounded like the car was coming apart ! So of course I tried it again and had the same results. Now I noticed the car is sitting low ! Hmmmmmmmmmm. So maybe I did tweek the springs ?- Top
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Re: Uh...One more thing
Jerry, Back in the late 70s there was an article in the Restorer that described how to rearch these springs and gave the end to end free arch (apart) dimensions that were needed for proper ride height. Did you use these dims. when rearching or just explain to the spring guy what you wanted ? Rich #2276- Top
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Re: Springs....the rest of the story
Tom, You sure did, been there done that (so many times that I purchased a second set of leaf springs so I could rebuild the ones I had just bent as I was in process of bending the ones currenty on my car)! You have a good eye to notice it now sitting a little lower. Jerry mentioned the Corvette bar that mounts to the top of the axle. IMO that bar is only marginal in preventing forward acceleration wheel hop. As long as the rear spring shackles pivot, the rear end housing, upon hard forward acceleration, can still rotate upward. This means the front section of the leaf spring is bending. Time well spent would to lay out the rear suspension out on a drawing board and study the forces being applied to the rear wheels under accceration, both forward and rearward. The Corvette bars do a good job during hard breaking (because there is no movement to the front spring eye), preventing axle rotational forces. IF you want to prevent hard forward acceleration axle wrap, the '60's style Traction Masters which mount from below the axle works! The key to preventing forward axle wrap is a bar that mounts to the axle from below the axle Regards,- Top
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My life vs. The Restorer
Using factory leaf dimensions (unloaded) might be a good way to define your re-arching goals if you are fixing an assembly line spring. Unfortunately, I seldom have that opportunity.
It seems like every car I repair has already been to automotive hell and back several times. I rarely work on a solid axle car that still has its original springs. Most of these springs were changed out years ago.
I usually describe the intended loaded effect of the re-arching to get what I want. Replacement springs, including GM's, may have a higher spring rate. Using factory leaf dimensions for them usually makes the car sit high.- Top
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Re: Springs....the rest of the story
Jim's right, as usual - I have original 60's Traction Masters on my '57 270, and it totally kills any axle hop or spring windup-induced weird rear axle behavior, and when you take off from a light, it just GOES - right now!
John- Top
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Broken leaf?
Four-thousand RPM Clutch drops? My! My! Shame on you boys! Try to do that on a '63 and you're likely to snap the drive pinion in two. And I said you couldn't overload a Corvette spring. But my real question is this: What's the incidence of broken spring leaves on solid axle models - common, somethings, or almost never? I don't think the three-link IRS models are known to suffer broken leaves.
Duke- Top
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Re: "62 with tired rear springs
I didn't read all the posts but I will give you my experience. Sorry if some of this was covered. I restored my original 62 springs winter before last. Original springs are grooved down the middle and are date coded. They are not reproduced with the groove. An original date coded set of springs can go for $750 and up depending on condition. I would repair yours if possible. That is assuming that they are not broken when you disassemble them. The specs on the springs are in an old restore article. I don't have it handy at the moment but could look it up if you are interested. They can be rearched by a good spring shop. Most big cities have companies that do this work. Sring liners are available from Corvette Central in the original configuration and look very nice. They also have the banding tool to install the bands. It is amazing to me how well these old cars ride when the suspension is as GM designed it. By the way someone had installed a fifth leaf with no groove in these springs at some point. I removed the extra leaf. Only the HD suspension had five leaves on solid axle cars. This is a job anyone can do given the proper (safe)jackstands and jack. Ceck the traction bar towers ahead of the wheel. They can be cracked or broken from the frame. One of mine was cracked. I had it welded and ground smooth. Good luck.- Top
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