<VV> Re: Front end alignment problem

[Frank DuVal]

>
>
>Hi all,
>I've recently completed my restoration (8 years) on a 64 spyder vert and went to setup the front end caster, camber and toe.  We were using a modern rack and all was going well until the machine said I needed almost 3/4" of shim for the left camber.  We said nuts to that and put almost half of that and the damn thing said we were right on at 0.01 deg.  What gives?
>But the real issue is when the caster dialed in nicely on the right coming out pretty much centered on the thrust rod threads, but the left showed us at -2 degrees.  We start to lengthen the rod and it went more negative, then toward positive but still negative but not to positive before we ran out of threads.  We raised the body, set it back down, bounced the car ... same problem.  Can't get positive caster on the left. Let alone 1-1/2 to 2 degs. Everything is new and in perfect shape.  The factory service manual says due to manufacture variances it may be necessary to place different amounts of shim on the two camber bolts to induce more caster.  Does anyone have experience with one side being way out on caster?
>I also tried loosening the six bolts holding the crossmember, raising the body to let the member hang and tried to induce a shift to maybe change the situation.  The x-member is not going to relocate, won't move at all because the six bolts pretty much locate it in one and only one place.  I thought this because the books don't supply any x-member alignment procedure anyway.
>Ideas?
>Thanx, Patrick
>  
>

The first suggestion is to start with the rear wheel alignment. Since 
you have had the car apart, the rear wheels need alignment including the 
re-arching of the transverse leaf if needed.  Even if this is a rear 
wheel drive car from the 60's, it is 4 wheel adjustable (both early, 
late and FC). In theory on an early you need a rear wheel alignment 
anytime the drivetrain is R&I or parts replaced. Wonder how many clutch 
jobs had wheel alignments?

Now that the rear wheels are propelling the car in a straight forward 
direction, do the front alignment. Again, basics first. Are all the 
control arm bushings and bolts tight? Ball joints without slop? Etc. 
Caster is the angle of the steering axis from vertical in the 
forward/rearward direction. The steering axis from vertical in the side 
to side direction is steering axis inclination. Confused? Most mechanics 
are...  Hence the "set the toe and let it go" remarks at not so good 
alignment shops (used to be $19.95 specials). The caster can be changed 
by adjusting the nut on the strut rod connected to the lower control arm 
so as to move the lower ball joint forward and aft of the upper ball 
joint. A line drawn between the upper and lower ball joint is the 
steering axis. So, caster can also be changed by moving the upper ball 
joint in relation to the lower ball joint, this is done by putting 
different size shim packs behind the upper control arm mounting bolts. 
Two means same end. Of course you may see that by moving the ball joints 
you are also changing the steering axis angle left and right, so the 
steering axis inclination is also changing. And the camber is also 
changing. Everything affects everything. Having been in the collision 
business I can tell you I have replaced many a steering knucle because 
it was bent. Not visibly noticable, but alignment was not possible until 
swapped out. As a last resort you could swap a knuckle or both and see 
if all is well. My first suggestion is to try different shim packs. 
Think about which way you need the strut rod to go and change shims 
accordingly. I think wheel alignment is the most not understood part of 
collision repair,  hence why people think a bent frame cannot be 
repaired.  Most can be with the right technician and the right money! 
Off soap box...

Frank DuVal