Rear spring replacement question
So, is there any functional or durability advantage with the Eaton Detroit unit?
Andrew
800-442-0335
http://www.muskegonbrake.com
Question for Andrew at Muskegon Brake: Regarding the post above from Dave Tracey, is it possible that the Ecklers spring is indeed not made to the original spec and therefore does always require thicker bolts?
I do see this note on the Corvette Central website, "When changing rear springs, the stack up on the spring and plate should be checked against the bolt length. This due to the variation or leaf and liner thickness. Spring mount plate and bolts are sold separately."
And from Eaton Detroit: "There are many aftermarket Corvette Leaf Springs availalble, but only EATON Detroit Spring offers springs that are nearly 100% correct.
We only use SAE5160 High Alloy Spring Steel in the manufacturing of all our Corvette Leaf Springs. But due to the reduction of available steel sizes we have to make a few slight changes. The thickness's of each leaf have been adjusted to sizes the steel mills now produce. Way back when, the mills would produce quantities as low as 5 tons of a size. Today over 20 tons of a size is the bare minimum of a size they will produce. And that is a lot of Corvette springs.
While the overall thickness of the spring have slightly increased, the fit, feel, function and performance of the springs are unchanged. The free arch have been lowered a bit from the factory specs in order to maintain stock ride height."
Sounds to me like longer bolts are in order for either supplier?
Thanks to everyone for your feedback!
Last edited by cam30era; Feb 15, 2012 at 10:25 AM.
Pilot Dan
Dave
The Best of Corvette for Corvette Enthusiasts


How does ones go about even checking the 'arch' of the springs?
How, or who, did you have 're arch' your springs?
If it was a business, what type would I look for around here?
Finally, approximately how much was your cost to re arch?
Thanks in advance,
RK

Dave
"Yes, but they'll just do it mechanically by over-stressing the spring, without the proper heat-treat, tempering and shot-peening, and it'll sag again eventually. Eaton Spring can do it correctly, but it costs more than just buying their reproduction.
Last edited by JohnZ; 03-30-2007 at 12:34 PM."
1) Getting the new spring into place was a frustrating PITA. My car is equipped with the one piece, welded N11 off road exhaust. I was working with the car up on jack stands, so removal of the exhaust was out of the question. I did disconnect the rear hanger, which gave a couple of inches of additional room. And the back of the car was high enough to allow clearance for the arch of the spring so that it didn't hit the floor. But it took me a couple of frustrating hours, and several "walk aways" before I was able to twist, wiggle, bang, push, and shove that SOB into place. I felt like Houdini trying to escape from a straight jacket. The problem was the short, straight top leaf hanging up on the spring mounting surface on the diff cover, together with inadequate clearance from the exhaust.
2) The new spring pack was only about 1/8" thicker, overall, than the one that I removed (uncompressed free state). I had ordered the recommended 1/2" longer attaching bolts, but they were too long (I checked before installation as I didn't want to risk cracking the diff cover). But getting the first thread started was also a royal PITA. Again, the arch of the spring was the demon. I had to first remove the lock washers from three of the bolts and start them, bringing them up just slightly snug, then I was able to install one bolt on the diff side of the spring with the lock washer. Got the second bolt & lock washer installed the same way. For the two bolts on the read side of the spring (away from the diff) I had to put the wheels & tires back on the car, let it down so the spring was compressed, and very carefully remove them, one at a time, and reinstall with the lock washer. After carefully torquing the bolts (with the suspension loaded), I measured the compressed thickness of the spring pack. Less than 0.10" thicker than the tired old spring.
If anyone has any suggestions for others who are considering doing this for the first time, please post your suggestions. I personally don't plan on doing this again anytime soon.
I did it the way you did, and it sucked. Agreed. But I used the Eaton spring, and I'm VERY happy with the ride height. DEAD ON factory spec.
That is a great idea about dropping the rear valence! You are right, that would have provided a couple of inches of additional clearance above the exhaust, and would have made all the difference in the world.
FWIW: my ride height with the Corvette Central spring is smack dab in the middle of the factory spec, too.
When I looked under the car before ordering, I thought I counted 9, leaves. But when I took out my existing spring today, I realized that it has 7 leaves from the heavy duty suspension (even though it's a SB 65).
I must have counted one of the liners.
Unfortunately, the replacement I ordered has 9 leaves.
Two questions:
Are there issues using a 9 leaf spring in place of a 7 leaf?
Is there any way to install the 9 leaf without dropping the exhaust? I can't seem to get the flat top leaves past the differential.
Thanks!
John
In order to get the clearance needed I removed the rear clamps and the exhaust tips, then lowered the mufflers as far as they would go within the confines of the rear quarters. I used jack stands to support the exhaust pipes on both sides of the differential.





















