Rear Leaf Spring Suggestions - Rebuild or Replace?
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 912
Likes: 47
From: Kansas City MO
Rear Leaf Spring Suggestions - Rebuild or Replace?
Hey guys, looking for thoughts on whether or not it makes sense to rebuild the rear leaf spring off my 71. I didn't really have any issues with it before it was removed, but not sure if I should just buy a new one instead? Any suggestions would be appreciated. Thanks.
Intermediate
Joined: Jan 2009
Posts: 32
Likes: 15
From: Kintzel NY
I would not rebuild old springs. If you aren't concerned about remaining stock, I would consider aftermarket fiberglass single leaf spring. I put one in my 73 Big Block Coupe in the early 80's, and have always been satisfied with it. I owned the car since 1974. My 1st Vette. It's on the road every summer. My back end was bottoming out on the country roads, so I decided a spring change was in order. When I got this thing from Ecklers back n the early 80's, I thought "How long is this going to last?" It only weighed 7-lbs, and appeared much less durable than the stock stack of leaves I pulled out. Well, almost 30-years later, it's still in there, and performng well.
Le Mans Master
Joined: Sep 2004
Posts: 5,116
Likes: 5
From: Livonia MI
Your original actually looks pretty good with no cracks. If the ride heights still ok, could just put it back in. Agree, If you're gonna do something, would get a composite job. You need to look out when torching in the area, or running exhaust to close though. Knew a guy, who put on a comp, and when getting the rear suspension serviced, came back with a stocker on it. Understandably, he was pretty upset, but the shop denied knowing anything about it. I mentioned it was probably a torch, and don't think he ever got it resolved. Maybe not a bad idea, if he would've taken some pictures.
Burning Brakes
Joined: Oct 2011
Posts: 1,093
Likes: 2
From: long beach California
Knew a guy, who put on a comp, and when getting the rear suspension serviced, came back with a stocker on it
sorry did you mean he had a comp spring and the shop replaced it with the stock steel an claimed to know nothing about it?
can i put a composition spring on my 79 without any fitment issues or will it not fit right?
sorry did you mean he had a comp spring and the shop replaced it with the stock steel an claimed to know nothing about it?
can i put a composition spring on my 79 without any fitment issues or will it not fit right?
Drifting
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
Are you looking for an upgrade? If so, you have your answer.
If the old spring had proper ride height and you don't have money burning a hole in you pocket, there is no reason to spend it where it's not needed.
Why rebuild something that isn't broken?
I'd just clean it up and put it back on.
Just my .02
Elm
If the old spring had proper ride height and you don't have money burning a hole in you pocket, there is no reason to spend it where it's not needed.
Why rebuild something that isn't broken?
I'd just clean it up and put it back on.
Just my .02
Elm
Melting Slicks
Joined: May 2009
Posts: 3,079
Likes: 315
2024 C3 of the Year Finalist - Unmodified
I rebuilt mine. Takes time and effort to clean and bead blast though. Paragon sells perfect repro plastic inserts for $49. Used Rust-Oleum primer. Really no big deal.
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Team Owner
Joined: Sep 2006
Posts: 31,278
Likes: 4,372
From: Westminster Maryland
Hi sr29,
I think rebuilding your original might be a good idea based on the many threads I read about people having problems with getting the rear ride height where it was originally was, after a spring replacement.
Regards,
Alan
I think rebuilding your original might be a good idea based on the many threads I read about people having problems with getting the rear ride height where it was originally was, after a spring replacement.
Regards,
Alan
Thread Starter
Burning Brakes
Joined: Jul 2009
Posts: 912
Likes: 47
From: Kansas City MO
Thanks for your input guys. I don't recall having any sagging issues or anything like that, so I should be okay. Think I will go for the challenge of removing the center bolt and breaking everything down to bead blast, prime/paint, and put back together with new plastic inserts. I love feeling the sense of accomplishment when completing something on my own and seeing the end result...
Drifting
Joined: Mar 2009
Posts: 1,461
Likes: 361
From: Monson MA
People say replace due to saving weight. But does this lend its self to a heavier front end? Due to relocating the center of gravity forward. I would think it would. Just asking if it matters. I my self will be rebuilding mine to keep the geometry as intended. Just a thought
Pro
Joined: Feb 2012
Posts: 577
Likes: 6
People say replace due to saving weight. But does this lend its self to a heavier front end? Due to relocating the center of gravity forward. I would think it would. Just asking if it matters. I my self will be rebuilding mine to keep the geometry as intended. Just a thought
Just offset the weight balance change by replacing the iron cylinder heads with aluminum cylinder heads. You'll shave a few hundred pounds, keep your weight balance, and increase power to weight ratio. All around victory.
Drifting
Joined: Oct 2010
Posts: 1,972
Likes: 6
From: Chester Virginia
stock spring
I didn't even undo mine since no inserts were gone, no leafs were broken. We replaced the bushings and the back two body bushings as well and I just cleaned it and repainted it black. If I were going to race it I'd have put stiffer springs, stiffer shocks, stiffer composite spring but with a stock L48 engine that's hardly worth the bother since it rides well as is. Once going 80 over a hill then hidding a dip I did bottom but that was because I was pushing it more than I ought to have been. I know my roads now before pushing it and it's just not an issue.
If I ever add another 150 hp to the car with new heads, etc. I might consider redoing the suspension physics but otherwise, not necessary for me at all.
If I ever add another 150 hp to the car with new heads, etc. I might consider redoing the suspension physics but otherwise, not necessary for me at all.
Melting Slicks
Joined: May 2009
Posts: 3,079
Likes: 315
2024 C3 of the Year Finalist - Unmodified
I neither wash the car anymore or drive it in the rain. Love to mash that pedal to the floor on sunny days though.
Melting Slicks
Joined: May 2004
Posts: 2,743
Likes: 845
From: Gulf of America
2023 C7 of the Year Finalist - Unmodified
2018 C3 of Year Finalist
I agree. I rebuilt my original spring years ago (sandblast/primered/dove gray paint/new liners) and got some more years out of it. Recently it finally got tired and I replaced it with an Eaton steel spring. Perhaps down the road, I'll try a fiberglass for the weight savings.
Advanced
Joined: Mar 2016
Posts: 54
Likes: 3
From: Austin TX
Dragging up an old thread. Was curious about rear spring replacement and if it is often needed. Sounds like there is no perfect option for the C3's out there - at least according to this article:
http://www.duntovmotors.com/tech-rear-leaf-springs.php
couple of times a week we are asked to give the plusses and minuses of composite vs. steel rear leaf springs. This is how we see it:
http://www.duntovmotors.com/tech-rear-leaf-springs.php
couple of times a week we are asked to give the plusses and minuses of composite vs. steel rear leaf springs. This is how we see it:
The TRW spring is the OEM replacement spring for the 81 and 82 Corvette. From 1963-1980, Corvettes came with steel rear leaf springs. In an effort to shave weight off the car to help with fuel economy, for the 1981 model year Chevrolet went with magnesium valve covers, a composite rear spring and a number of other weight saving substitutions. The spring change saved about 20 lbs; a huge savings for comparatively little money. To the end user, the twenty pounds is equivalent to about two and a half gallons of gas; not exactly earth shaking for the average Corvette driver.
Unfortunately the composite spring weight savings was right where the Corvette least needed to lose weight; low and behind the rear axle. The steel spring is like ballast in a racecar, right where it needs to be; low and behind the rear axle.
Composite springs don’t lose their spring rate over time. A 315 lb spring will stay 315 lbs until it breaks. Yes, that’s what sends composite springs to the dumpster; a rock in just the right place. Hit on edge by a road hazard, a composite spring will often de-laminate. It will turn a milky white at the point of injury and its service life is over. A steel spring will slowly lose its spring rate over time, but it will never break.
The softest TRW composite spring is 315 lbs. Most C2 and C3 Corvettes came with 196 lb. steel rear springs. After 20 years or so, when they are ready for replacement, their effective spring rate has eroded by as much as 40%. Replacing the original spring with a new stock steel spring makes a big difference; a 40% difference. Changing to a 315 lb spring would be a change of 270%, and you would have a completely different automobile.
The spring rate of the 78-80 OEM factory steel rear spring was 260 lbs. You can order a 315 lb spring for a 78-79, but for anything newer than that, you have to chose between 345 and 355 lbs. That’s a heavier spring rate than we run on our racecars, so you can imagine it’s not the softest ride on the planet.
One more thing that may or may not be a big deal to a street driven Corvette: The steel spring is at least somewhat progressive in its spring rate. In our custom steel springs that we use for our racecars, we individually arch every leaf to achieve an almost linier rate progression. This helps handling a lot, and we see it in our lap times. Obviously that’s not possible with a composite spring.
In summary:
Composite spring Advantages:
• Light weight
• Permanent spring rate
• Permanent spring rate
Disadvantages:
• Cost
• Durability
• Limited spring rate options
• Often much stiffer than stock
• Durability
• Limited spring rate options
• Often much stiffer than stock
Last edited by SunglassesGuy; Jul 15, 2016 at 01:36 PM.
