Rear Leaf Spring

Eden72Vet · 07-13-04, 02:14 PM

I have replaced the connecting bolts and rear leaf spring in my 72 vette. I knew the old spring I was replacing was worn out. However, when I replaced it, the car now sits really high in the back. I have about 8 inches between the top of my tire and the wheel well. I replaced it with the stock leaf spring from Ecklers. I have drove the car for about a week, and the spring does not seem to be settling much. Does anybody have any experience lowering the rear with a strong leaf spring, or does anybody have any ideas on how to get the car lower?

Bob Chadwick · 07-13-04, 03:05 PM

A lot of people have had this problem when they replace the metal spring with the fiberglass. If I read you right, you replaced with the steel spring. Have you got the spare, etc., back on the car.

You can lower the car by loosening the nut on the spring end bolt. The tighter it is, the higher the car. It pulls the trailing arm down to the spring increasing the gap. If you tightened the nut beyond where it was, you will raise the rear of the car.

If your bolt is not long enough, you can buy longer bolts. All the vendors sell them.

Eden72Vet · 07-13-04, 08:35 PM

bobchad,

You are correct in that I replaced the fiberglass spring with the steel spring. When I ordered the stock steel spring, I was unaware that there was a difference. The nut is not all the way tight. I considered using the longer connecting bolts, however, I am looking for about 2-3 inches of a drop, and it appears the bolt may rub against the tire if I use longer bolts. I am running 255/60 size tires.

What I am considering doing, is taking 1 or 2 of the top leaf springs out of the spring. I think that will drop it down and weaken the spring a bit. Then, at a later date, if need be I could add them back. Any thoughts on this would be appreciated.

07-13-04, 08:55 PM

EDEN, i wouldn't remove leafs. yes it will lower the back, but .i feel, it will cause the rear end to handle poorly. the car will tend to be loose,wallowing in the corners.also your shocks won't be 'in tune' with the lighter spring tension.
just my opinion. i would try the 8inch bolts first. they can be had fairly cheaply.

Robin

Bob Chadwick · 07-13-04, 08:59 PM

Quote:

Originally Posted by Eden72Vet

bobchad,

You are correct in that I replaced the fiberglass spring with the steel spring. When I ordered the stock steel spring, I was unaware that there was a difference.

If you replaced a fiberglass spring with a steel spring on a 72, then someone had already replaced your spring. It was sometime after my 77 that the fiberglass spring became stock. You appear to have gone back to stock. The problem is normally with the fiberglass spring, not the steel spring.

Are you at the very bottom of the bolt. If not, I would loosen it until there is no contact with the spring and then finger tighten plus a turn or two with a wrench.

I wouldn't remove anything from the spring. It could be a safety issue. Call Ecklers. Explain your situation and see what they have to say. Vette Brake Products could also help you. I just don't know if they would have an interest since it's not their spring.

Eden72Vet · 07-13-04, 09:00 PM

My concern with the 8 inch bolts, is that if I extend the current bolts I have (just purchased new) they would be rubbing against the tire. I am not worried about the cost of buying the 8 inch bolts, I am just worried it will be rubbing against the inside of my tire.

Bob Chadwick · 07-13-04, 09:04 PM

This shouldn't be a concern with the 8 inch bolts.

brusso · 07-14-04, 12:59 AM

Did you go with the 9 or 7 leaf spring? I recently replaced my worn 9 leaf on my 75 with the "heavy duty" 7 leaf P/N A7091. Very happy with ride hight. If you look at the Eckler's web site and compare the appearance of the 7 and 9 leaf, you'll see the differrence in arch. 9 leaf has a much more radical arch.

JohnZ · 07-14-04, 07:04 PM

The original 9-leaf and heavy-duty 7-leaf springs both produced exactly the same ride height at the same design load (that's how leaf springs are designed); the difference was that the spring load rate at the design height for the 7-leaf spring was almost twice as high as the 9-leaf spring. The amount of arch difference between the 7-leaf and 9-leaf springs with the spring out of the car in its free state doesn't mean anything; both have exactly the same camber at design load. The 7-leaf spring will put the back of the car at the same height as the 9-leaf, but it will ride much harder. Don't remove any leaves from the spring - you'll risk breaking it. I have no idea who makes Eckler's replacement springs, but the most accurate ones are made by Eaton-Detroit Spring ( www.eatonsprings.com ).

brusso · 07-15-04, 01:57 AM

Quote:

Originally Posted by JohnZ

The original 9-leaf and heavy-duty 7-leaf springs both produced exactly the same ride height at the same design load (that's how leaf springs are designed); the difference was that the spring load rate at the design height for the 7-leaf spring was almost twice as high as the 9-leaf spring. The amount of arch difference between the 7-leaf and 9-leaf springs with the spring out of the car in its free state doesn't mean anything; both have exactly the same camber at design load. The 7-leaf spring will put the back of the car at the same height as the 9-leaf, but it will ride much harder. Don't remove any leaves from the spring - you'll risk breaking it. I have no idea who makes Eckler's replacement springs, but the most accurate ones are made by Eaton-Detroit Spring ( www.eatonsprings.com ).

You learn something every day.

Swamp Donkey · 07-15-04, 07:40 AM

Quote:

Originally Posted by Eden72Vet

My concern with the 8 inch bolts, is that if I extend the current bolts I have (just purchased new) they would be rubbing against the tire. I am not worried about the cost of buying the 8 inch bolts, I am just worried it will be rubbing against the inside of my tire.

I have also heard that you can invert the spring end bolt if you are worried about tire rub. My understanding is with the longer bolts you can effectively lower the rear ride height about an inch which will have a very slight raising effect on the front ride height. There also could possibly be some other suspension issues--most of us measure ride height from the center of the wheel well down to the ground and look for something between 26 and 28 inches with no more than 1 inch difference between them. I do believe the correct measure is from the lower control arm down.

Eden72Vet · 07-15-04, 11:11 PM

I have been talking with Eckler's about the situation. They have basically told me 2 things. 1) I can go with longer bolts to lower it. Which I may do that after a month or so. 2) The spring will settle, and to help it settle I can place some weight back over the wheel well. (Back where the t-tops are stored). I am going to give it some time to settle, because it rides so well now, compared to the old spring. Also, I am going to let it settle, because it was so difficult getting the bolts lined up with the leaf spring.

By the way, Swamp Donkey, I am just under 32 inches from the top of the wheel well to the ground. It is kind of like driving a 4X4.

Swamp Donkey · 07-16-04, 09:32 AM

Quote:

Originally Posted by Eden72Vet

By the way, Swamp Donkey, I am just under 32 inches from the top of the wheel well to the ground. It is kind of like driving a 4X4.

32"---Holy Dawg Doo--a nice little tip on installing the spring bolt is put another floor jack or similar under the tire and raise it up alittle--should help the bolt drop right in.

ltmark · 11-30-04, 02:10 PM

I have an '85 with good springs (orig I think)...the ride is a little rough/stiff. Just wondering is I can lower the nuts a little, which will raise the car a little...but will is soften the ride also? This would put the nut below the cotter pin hole, so I would throw on another nut and lock them together! OR, would this make little, if any difference?

citadel · 11-30-04, 02:28 PM

I have a 73 BB that since I bought new I have replaced 3 springs and 3 rear end covers. I think it had something to do with hole shots! The last replacement made was with parts supplied by Muskeogen Brake. The rear end cover is beefier and I got the HD spring. I have not had a problem since, but the rear end height is up about 2". Had I had to do it over again I would opt for the fiberglass spring. I can drive over a dime and tell you what year it was minted, but nothing breaks! DR