I have a 66 convertible with stock upper A-arms (although the mounting shaft has been offset by 1/2 turn) and the Arning modification (which also moves the upper arms back 1/8"). The car has the stock strut rods and lower control arms.

The alignment shop I went to a few years ago only put a small amount of caster, and the camber appeared to be a little outside the specified values. The car drove OK, but needed a lot of corrections on back roads or in wind.

I've read about issues with bolts coming loose and shims falling out when there are large front-back differences in the thickness of the shims on a given A-arm.  Bullet Bob was kind enough to tell me about his wedge solution and it sounded great.  The only issue was that I didn't have the tools or material to make a wedge that would work.  Nevertheless, Bullet Bob's single piece solution was the inspiration for my implementation.  

I made a couple of plates that spanned both control arm bolts and wired the shims to the plates once I had the alignment numbers I wanted.  Admittedly, this is not going to square up the clamping surfaces for the bolts as a wedge would, so it's possible, if not likely, that the fasteners could loosen over time.  However, if that happens, the shims won't fall out of position.

I ended up with 4.2° of caster and 0° of camber on the left side, and 4.4° of caster and -0.2° of camber on the right side. The left side shim stacks were 3/16 front and 1/32 back. The right side are 15/32 front and 3/32 back. The mounting plate is 0.044 inches thick, so that adds into the total shim measurement front and rear.  I put blue thread lock on the bolt threads before I torqued the nuts for the last time, hoping the extra measure would make the nuts more resistant to loosening.

The car drives much better - straight with very few corrections needed on back roads, even fewer corrections on primary roads. I'm happy.

I've posted some photos of the process, starting with fitting a cardboard template on a spare upper control arm, then using the template to cut out two metal pieces ( I made them from some sheet I had laying around - I think it used to be a VCR chassis or something).  I put a bend along the top of each plate and used a shim as a template to determine where to drill the hole in the plate.  Lastly, I worked through the alignment process, adding and subtracting shims to get the numbers I wanted, and wired the shims to the plate (the photo shown is an interim step and has far more shims on it than were used in the final iteration).  The next-to-last photo shows the plate and shims as installed, and the final image shows the worksheet I used to sneak up on the alignment numbers I wanted.






 

Last edited by John Ha (3/05/2024 9:25 AM)