PeteL46

1st let me say I bought the car in 84. Restored it it 93. Nut and bolt. Complete born with car that had 60K on it. 8,000 miles since restoration. 2 yrs ago it started wandering and last season it seemed worse. I decided to try and adjust it to get in 2 more rides before winter sets in.. Big mistake.. Car was all over the road, actually scary to drive at speed. Come to find out the tires were severely worn on the inside. Over winter I purchased new tires. Had alignment done yesterday. Still wonders and gets worse the faster I go though much better. I've searched the forum and read many threads. Still are unsure what the specs should be. Her e is a picture of the print out and the one from the AM. The align. shop said the AM specs weren't clear enough so they went to internet. What spec should I bring back to the shop?
I've also included a few pic's of the chassis when I repaired the rad and water pump last September.
Thanks for the help.
[IMG]
http://i1272.photobucket.com/albums/y382/crowleyl46/unnamed1_zpsa6314924.jpg[/IMG]

zwede

In your last picture the car sits very high. Has this been corrected? It needs to sit at the correct height to drive well.

As for alignment, factory specs were for bias ply tires. I take it you put radials on it? I've found the following settings to work well:

Front
Camber: -0.5 dgr
Caster: +2.5 dgr (or more if it will take it)
Toe: 1/8" in

Rear:
Camber: -0.75 dgr
Toe: 1/8" in

Did the alignment shop check for bad bushings, ball joints etc? You don't have many miles on it, but 20+ years can rot out bushings.

mac79vette

I am close to finishing my 1979 Corvettes restoration and have been researching what I am going to do with my alignment. I have had my car for 16 years and seem to always have issues with the alignments and the shops not knowing what to do with it or will not use other than stock alignment angles. My plan is to just do the alignment myself. I plan to use a camber/caster gage and string the car to set toe and to make sure the rear is aligned to the front. But to answer your question look at Vette Brakes and Products or Van Steel and they have different alignment specs for different situations. From VBP there daily street is Front toe 1/32 Camber 0 Caster 2 3/4 rear toe 1/8 Camber 0.
On the C3 vettes rear toe in is very important because if the toe in is to little than the wheel will toe out when you corner or hit bumps causing a rear steer situation that will make the car scary to drive.
Your car looks really good and you did a really good job with the attention to detail.

Alan 71

Hi Pete,
I agree that the car looks very nice!
I also agree that the car appears to be sitting quite high both front and rear.
Have you checked the ride height dimensions….UPC 0, Sheet A-12 ?
I believe the car needs to be at the factory ride height for the factory alignment specs to be used.
Were the springs front/rear replaced when the car was restored?
Regards,
Alan

PeteL46

Here are some close ups of my clearance of rear tires and spring. The front tires are 245/60 so they don't fill the well. New springs in front 93, original in rear. I added the spec sheet. All bushings are urethane.

PeteL46

The front springs were replaced with OEM from chevy dealer. The rear is original. I posted a shot of the rear spring and the rear tire clr.

PeteL46

mac79vette, thanks for your response. I looked at VBP and many others. What set up do I use. I have one shot for free for a re-due align,
. Thanks for the attention to detail comment.

zwede

There were many different springs. At the factory they selected the ones that matched the options on the car. It is possible the dealer sold you a generic one-size-fits-all.

I'm surprised the original rear spring sits so high. You can get 2" longer bolts that will give you more adjustment. The half shafts should be about parallel to the ground. Yours are angled quite a bit.

Here's a shot of mine that sits right at factory height.

Alan 71

Hi Pete,
The AIM page allows you to measure from the ground to the center of the wheel well front and back… the dimensions are based on a tire height of 27". You can adjust the dimension for your tire's heights.
The page also allows you to measure the suspension itself which disregards the tires' dimensions to see where you are.
Regards,
Alan

It does look high. Remember, longer bolts treat the symptom, not the cause.

zwede

Looking at what they set it to: You need more toe-in front and rear. That's your wandering right there. 0.20 dgr is good. Can even go 0.30 dgr in the rear as it likes to toe out on bump. You should consider going to negative camber in the front, it will handle better. Your front camber is not making it drive badly, though. Finally you want more caster to make it more stable at speed. Caster increases steering effort, improves return-to-center. They should be able to get 2.5 dgrs.

DUB

Some people often forget that the power steering control valve can be out of adjustment...and can actually cause the car to turn due to it not being balanced correctly....even though the alignment numbers are perfect.

Just a thought. I always check the control valve before an alignment. A simple easy check/adjustment.

DUB

PeteL46

Zwede; I see yours is much lower. The car ran perfect for 7,900 miles. I purchased most of my parts from the same dealership back in 92. I new the parts guy prior to the resto so he new my car 350/350 1970.. The car tracked well for 7,900 mile +-. Then it seem to develop what I found to be bump steer. I would hit a depression in the road and the car would shoot one way or the other;got worse over 100 miles, pretty scary when it first happened, I was kinda racing an 04. I thought it was a loose wheel bearing, loose shock, etc. Then I noticed the inside tires very worn and attributed the tires a the culprit for the bump steer. I dismounted the eagle vr gator backs and moved to the other side. It helped. I agree the car is high but it drove so well for x amount odf miles.

PeteL46

Dub; I checked it 2 yrs ago when this so called bump steer began. Though I thought of it again yesterday. On the ride home yesterday I had to put pressure to the left for the car to track straight though the contour of the road would let the car go in that direction when I let go of the wheel.

PeteL46

Alan, I will check; are these dimensions plus or minus 1/32?? If it's off what's the fix? how does my rear spring/bolt/1/2 shaft look?

zwede

Since it happened suddenly I'd take a real close look at the bushings. Especially the trailing arm where it mounts to the frame as well as the front control arms.

PeteL46

So: .2 in front; .3 in the rear. Neg camber in front (Set now at .5 to .6)
how much? 2.5 deg caster (now set at 1.3 and 1.8)
How do I set the car lower to the ground?

I see your suggestion.. I'm a slow typist!!

PeteL46

Off to an AA meeting.. Sober 8 yrs on the 17th!!!!!!!!!!!!!

Photo of one of the A arm bushing.

zwede

For the front, first make sure the springs have properly gone into the grooves in the lower a-arms. Service manual shows what it should look like.

If they have, you have two options: Either replace the springs and hope the next set is better, or cut your existing springs.

Rear (like mentioned earlier): use the 2" longer bolts. I still have no explanation why your car sits so high in the rear with a factory spring.

Your bushing looks fine, but sometimes you can't tell just by looking at them. See if you can find a shop that has a "suspension wiggler" (don't know the technical term). You drive onto it and it rapidly moves a couple inches side-to-side. While it's doing that, the tech walks under the car and watches the suspension. A weak bushing, ball joint etc is immediately obvious.

PeteL46

I do know one thing that when I put everything back together during the resto I didn't follow nor did I know there was a sequence of events such as the A arms bushing bolts needed to be tightened under load. All suspension bolts where tighten as they were installed, not under load or weight of the car. For twenty years the nose always sat high. What I mean is the front of the hood or point, center line was always lower than the body/head lamp area/center line. It wasn't until I took out the radiator as a unit with the rad support that it changed. When I put everything back together again it was then I noticed it now aligned properly. The body settled into its proper position. It has to come out again because it still has a miniscule leak. while it's out I think I'll loosen all of the A arm bolts, bounce on it a little and see what happens, of course follow the proper procedures. I remember putting the front springs into the proper notch or perch when assembling. I'll recheck. I there anything in the back that need to be loosened?

doorgunner

For eight years!?!?!?!?!?!?!?!?!?

That's great!

I was clean for 20 years....got stupIed...now reclaiming "lost ground"!

Those look very good....My A-arm bushings were cracked/squished out.


8 years!