70BBvert

Haven't been on in a while, but need a 2nd opinion. Recently replaced tires and in the process I noticed that the drivers side wheel is not centered in the wheel-well, it is noticeably forward. After reading through a bunch of old treads and measuring the wheelbase and the distance between the reference hole & center of the lower ball joint the divers side is approx 3/8" forward.

A little history

• When I rebuilt the car I had the frame straitened to correct the previous owners accident/frame damage, passenger side. It was done on a frame machine with laser measuring system. frame was returned to factory spec.
• Original factory lower control arms, new bushings, & shafts & VBP offset upper arms
• Car has been finished for 10+ yrs, alignment was in spec, no pulling or drifting
• P/S frame measurement is 46 1/16", D/S measured approx 46 7/16"
• Wheel base on P/S is 98", D/S is 98 3/8"
• I measured from the factory reference hole to center of a front control arm mounting bolt, measured the same on both sides
• It's been this way since the car was finished

I believe the D/S lower control arm is bent, however there is nothing obvious.

Thx for your help & opinions

Jim

wwiiavfan

If a lower control arm was bent enough to create a 3/8” wheelbase difference, I would think you would see a buckle somewhere on the arm stamping.
Id be looking at the arm mounting points. I don’t believe these would have been checked by a frame straightening shop?? If the mounts are tweaked left or right even a little, it would kick the lower ball joint forward or back a good amount because of the length of the control arm.
Are there an extraordinary amount of shims on the upper arms to get proper alignment? How about the rear control arms?
There are folks on here with lots more experience than me that should be able to point you in the right direction.

Bikespace

Do cross measurements, too, to check for squareness. Can you see, or measure, a difference between the control arms?

This similar thread has never been resolved, but it might give you someplace to start.

https://www.corvetteforum.com/forums...e-rubbing.html

Steve Stroman

Look at the LCA mounting point to the frame. Mine got partially torn off (they're really crappy welds) and my tire moved forward.

70BBvert

Thank you, I don't see any damage or movent at the lower control arm mounts. I had stripped the car completely and had the frame upside down for cleaning & painting, etc. Didn't see anything then either. I also don't see any bends or wrinkles in the control arm. Had it off Sunday and tried to compare to passenger side, holding it upside down on my back on the driveway... It didn't work out so well Forgot how heavy they are.

Sometimes its hard to see damaged parts until you compare side by side to a known good part. Found that out with the relay rod...

Found this thread yesterday also https://www.corvetteforum.com/forums...unt-specs.html Front is exactly 16" C - C, I have to put the car on jack stands to measure the rear.

The frame was out of square, but was pulled back into spec

I swap a new arm this weekend and measure to the ball joint and go from there

Jim

leigh1322

My frame had also been in an accident.
But also the lower a-arm mounts were welded incorrectly at the factory, 50 years ago.
They are supposed to be parallel. Mine were not even close.
So I cut one off and welded on a new bracket after I moved the rear side of it 3/8" and the ball joint moved 3/8" too.
Problem solved.
Measure yours at the lower a-arm shafts. They should be 16" center to center. And parallel. Within +/- 1/16" But QC varied in the 70s. Alignment shims "sort-of" takes care of any bad QC.
You will not find this measurement on any GM spec anywhere. 12 guys measured 12 cars to get that #.

70BBvert

Put the car up on jack stands toning and double checked measurements. Lower control arm mounts are solid & measure 16" center to center front and back. I also measured from the reference hole in the frame to the opposite sire rear lower control arm bolt. Within 1/16" side to side, so frame is square.

I did take a close look at the lower arm on drivers side and see some small differences in the bends at the bushings, visually the bend is tighter at the front, the gap at the bushing is tighter, and the bushing is not fully seated.

Have new arms on the way, should be hear tomorrow. If weather cooperates they will go one this weekend

leigh1322

Well if the frame is good, then the only thing left is the a-arms.
They must have gotten damaged during bushing installation, either this time, or years ago.

70BBvert

Agreed, decided to upgrade to Global West lower arms... while I'm at it

Jim

gkull

I have a rust free southwest frame and never in a wreck. But years ago I was driving it with 295 front slicks and 700# coil overs and I notice that something didn't feel right so I took it to an alignment shop. I had developped a crack in the frame where the lower A-Arm connects. I cut out the cracks with a plasma cutter, welded, ground flat and then fish plated over that whole frame area so it wouldn't happen again. I fish plated the drivers side while I was at it.

When you bend a frame and then pull it back to "Straight" it is weaker than original. Time and use can bend it to get your problem. I would see what is out and straighten it and then fish plate reenforce it.

70BBvert

So after 5 hours on Saturday, both control arms were replace with Global West lower arms. Wheelbase is now even & back to spec on both sides

https://www.globalwest.net/cta-31l.html

Wheelbase is now even & back to spec on both sides. Cut the springs a bit to lower the ride height at the same time, stance is much better, but need to tweak the rear ride height a little

Then its off for a wheel alignment...

Thanks for all the tips & suggestions

Jim

Bikespace

Thank you for updating the thread with a resolution!

cagotzmann

Interested in trying DIY Alignment, its not that hard to do.

Here is what I do. Part of the method also checks front vs rear axle angle alignment as well.

My DIY Alignment method - CorvetteForum - Chevrolet Corvette Forum Discussion

leigh1322

Glad it worked out and you are happy with it!

Great resolution.