Ride height thoughts

[anchors]

I have been reading a lot of questions about uneven rear ride heights on C3s. Its hard to believe that some sort of adjustable device for the spring bolts has not been thought of. I wonder if double nutting with the lower nut being a nyloc or something similar would work. I would like to hear some thoughts on that.

 

[Bob Heine]

Anchors,

You're right. Almost all of the Corvette parts vendors sell grade 8 replacement spring bolts with nyloc nuts. Many of them also sell longer bolts to allow you to lower the rear suspension ride height. Here's a link to one of Corvette Central's offerings.
http://www.parts123.com/parts123/yb.dll?parta~dyndetail~Z5Z5Z50000050g~Z5Z5Z530706~P24.95~~~~S3FP0WTOEG76109913832a~Z5Z5Z5~Z5Z5Z50000050G

I wouldn't use the bolts to level the rear ride height. If the car is leaning to one side, there is probably a problem that needs to be fixed, like a broken spring leaf or a broken/loose center mount bolt (or a broken ear on the differential case cover). Even if they aren't broken, it would be better to replace the spring on a 40-year old car than to adjust the bolts to mask the real problem.

 

[GTR1999]

The problem most times is related to replacement rear springs. Since GM discontinued the steel springs years ago the aftermarket is the only source unless you gather some used originals to make up a good one. The aftermarket springs were never arched correctly and the rear of the car sits up 1,2,3" like you have air shocks. The 8" bolts usually work to allow the rear to get back into correct height. You have to watch if you use longer bolts & thin tires that the bolt doesn't hang lower then the wheel in case of a flat tire. That would lead to the bolt dragging on the street and causing some steering issues very quickly.

 

[73shark]

Correct rear spring arch?

With the car at rest, how much arch should there be in the spring? Or should it be basically flat?

 

[Gohot]

Trying to understand

Ok I gather that the ride higth is determined by how much preload is applied on the leaf springs, ie. length of bolts and the tightness or use of threads on the bolts. In other words, if you use up more threads bringing the suspension closer to the spring end, you effectively raise the car. If you allow less threads to be used, you lower the car.... is this right?

 

[Vettehead Mikey]

With the car at rest, how much arch should there be in the spring? Or should it be basically flat?

There should always be at least some positive arch with an OEM spring. The angle of the half shafts with respect to the ground is the most important. They should slope downwards from the diff to the wheels.

In other words, if you use up more threads bringing the suspension closer to the spring end, you effectively raise the car. If you allow less threads to be used, you lower the car.... is this right?

That's right- except it doesn't change the preload on the spring, it simply changes the distance between the spring end and the trailing arm. It's similar to adjusting the chains on a child's swing set- shorter chains= higher swing seat.

 

[Gohot]

Hmm, that was as I had envisioned, thanks