73 Ride Height Adjustment
Thread Starter
Intermediate
Joined: May 2007
Posts: 48
Likes: 2
From: Reading PA
73 Ride Height Adjustment
Ok, I have the same problem many others have encountered. I bought a new leaf spring at Carlisle last year from Muskegon Brake. I dropped the body a few weeks ago filled the gas tank and drove the car. My rear ride height is about 30 inches and the AIM states 27.03 inches. I should have searched the forums before buying a spring from this particular vendor. Anyway the nuts are at the very bottom of the 6" bolts. The question is whether buying 8" bolts will help. Is the bolt length ratio 1:1 for ride height? If so getting 2" longer bolts will only bring me down to 28". However, the car may settle this extra inch over a period of time. For me, the longer bolts will be a short term solution before I can buy and install a spring that will give me the correct ride height for my car. Anybody measured before and after installing the 8" bolts to see how much actual lowering you achieved?
Thanks, Dean
Thanks, Dean
Melting Slicks
Joined: Aug 2004
Posts: 2,063
Likes: 1
From: Beverly Massachusetts
have you driven or moved the car since installing the new spring? because the vette is an IRS when you lift up the rear of the car the bottom of the tires want to push in so once you put the car back on the ground you will gain a few inches till it has been rolled or driven. if it has been moved or driven then how many miles have you put on the car with the new spring and and long have you had it on the car?
Thread Starter
Intermediate
Joined: May 2007
Posts: 48
Likes: 2
From: Reading PA
The spring has been on the car about 3 months with the body on. The car has been driven only about two miles since the body was dropped. I really didn't notice a significant difference in rear ride height after the car was driven the first time.
Burning Brakes
Joined: Jul 2008
Posts: 876
Likes: 0
From: Canastota Ny
the longer bolts will give you more adjustment. the 8" bolts are what you want. but i thought there were 10" ones too. and is the ride height REALLY that important that you might end up off by 3/4? mine sits at 28-3/8 both sides. good nuff for me.
Last edited by 1nicecorvette; Mar 25, 2009 at 09:34 AM.
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
I had a similar issue with mine and installed longer bolts which solved the issue. I had trouble getting them from the usual vendors, they were out of stock so I bought some from Caterpillar. Very high strength bolt, coarse thread so you need a different nut.
Just in case you get stuck.
Just in case you get stuck.
Advanced
Joined: Sep 2005
Posts: 54
Likes: 0
From: Cheshire CT
I do not believe it is a 1 to 1 adjustment with the longer bolts. When I did mine I started with the 8 inch bolts and it was riding right around the same height as yours. I swapped out the bolts for the 10 inch and it brought it down some but not the 2 inches I needed. I ended up having to swap out the spring (twice actually) and even with a lower arched spring the 8 inch bolts still had an unacceptable (for me) ride height. I ended up back with the 10 inch bolts. Careful when you use the 10 inch though because if you get a flat tire the bolt will hit the ground before the rim. I can't even imagine what that would do to the rear suspension. I only needed 9 of the 10 inches to get the ride height right. I am hoping if I cut the extra inch off both sides I will be O.K. in the event of a flat.
Good luck
Good luck
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
Yes catepillarv sells 8 9 and 10, good stuff.
If that does not solve you still can rearch yourself the iron spring by opening the bolt that holds the 7 or 9 leafs together and then individually a bit rearching each leaf a bit...then just put them all back as one package and voilaaaaaa
If that does not solve you still can rearch yourself the iron spring by opening the bolt that holds the 7 or 9 leafs together and then individually a bit rearching each leaf a bit...then just put them all back as one package and voilaaaaaa
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Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 331
From: Indy Indiana
really ideally what you want is your half shafts to be exactly horizontal to the ground.. whatever height that equates to.. this height will be the least stressfull on your ujoints and bearings..
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
The Muskegon spring has way too much arc to it for a car to have a normal ride height in the rear. At least for our cars that had a steel spring originally. The shop that rebuilt the rear suspension on my '69 initially installed a Muskegon spring with the stock 8" bolts. It had about 4"-5" of space between the rear tires and the fender. My first thought was to have the longer 10" bolts installed, but I thought about the problem a bit more and told the shop to use a VB&P spring which they did. With the 8" bolts the ride height is proper. Muskegon was the OEM supplier for the '81/'82 cars, but I don't think it is the right spring for older cars that came with a steel spring. That's my story and I'm sticking to it.
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
You do not want to go longer than 8" bolts with 15" wheels. Any longer and you risk gouging the side wall of the tires under hard cornering plus the risk of the bolt dragging on the pavement in the event of a flat tire as mentioned before. Best thing is to get a composite spring from VBP and use the 8" bolts supplied with the spring. You will have the correct ride height. Make sure you return the spring to Muskegon and ask for a refund.
Melting Slicks
Joined: Jun 2003
Posts: 2,802
Likes: 241
From: Niles, MI
The Muskegon spring has way too much arc to it for a car to have a normal ride height in the rear. Muskegon was the OEM supplier for the '81/'82 cars, but I don't think it is the right spring for older cars that came with a steel spring. That's my story and I'm sticking to it.
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
Pete
Instructor
Joined: Apr 2007
Posts: 184
Likes: 1
From: Atlas is shrugging KC, MO area
Bottom line is that the stock springs bolts were 6" long. If your new spring has so much arch that 8" bolts won't give you the proper ride height (half shafts parallel to street as previously mentioned) then either return it or get it rearched.