i see recently a lot of posts about steering ... and caster . The more , as i understand , the better for steering , but harder on effort needed .

With the oem arms , i read to put shims to get the desired camber , and less shims at the front bold to get positive caster.

How much difference can we do that way with shims ? Will less shims on front bolt also alter camber ? and to what degree ?

Is there a "optimum" setting in shims thickness differences for a bit negative camber and max caster ? Or does all depend the specific car ?

 

Warning: I am not a professional alignment expert, but I did it on R66 and it works for the cruiser.
Here is what the GM Service Manual Section 3-5 says about shimming:
"Caster - change shims at either the front or rear of the shaft. The addition of shims at the front bolt or removal of shims at the rear bolt will decrease positive caster. One shim (1/3 2") will change caster (approx.) 1/4°. Camber - change shims at both the front and rear of the shaft. Adding an equal number of shims at both front and rear of the support shaft will decrease positive camber. One shim (1/32") at each location will move camber (approx.) 1/5° (Chevelle and Camaro); 1/6° (Corvette)".
I started with the maximum shims on the rear bolt to obtain maximum Caster. I ended up with about 1.5 degrees on each side. Then I added shims to the front bolt as needed to get 0 degrees Camber. The caster is reduced when you add shims to the front bolt and not the rear also.
These cars were built to utilize positive Camber due to bias ply tires. Radials require 0 degree or negative Camber. To obtain more Caster and 0 degrees negative Camber, Moog sells offset upper control arm shafts. For the performance (track) alignment, most recommend more negative Camber. Thus adding more shims to both the front and rear bolts equally.
I believe each car is different due to age and sagging of the frame. I don't know that a specific thickness shim pack will work on every C-2. This problem is even more pronounced on the cars with front subframes, as the total shim pack thickness on one side may be greater that the other side. I discovered this on my 68RS Camaro.
I apologize for getting carried away and providing more than you asked for. Hope this helps.

Ron

 

Sure Ron , thanks !

I can follow your suggestion , as i never read here :

start with max shims at rear bolt ( i assume full threaded nut ) , then add shims at front bolt to get the desired camber. The caster result is then at max positive possible .

Okay , will try that and see what it gives.

 

I think you'll find this old thread useful. Pay particular attention to posts 4-8.
Caster

 

Being a "Retired Red Neck", I aligned both car with home made tools and skid plates and levels. I figured the only way to get maximum Camber is to use maximum shims on the back bolt, but there is probably a better way. I thought about longer bolts front and rear, but I think they are only helpful to the point of obtaining the desired Camber. If I were racing the car, I would seriously consider the offset control arm shafts.
Hoping I did not mislead you, but it worked for me.
Ron

 

Ron - that’s pretty much my approach too. I start off with max shims in rear and none in the front. Then I add shims in front until I get to 1/2 degree negative camber on both sides. Then I check caster and hope it’s pretty close from side to side. I don’t worry if caster varies slightly which probably distinguishes me from a professional with high-tech equipment. Then I check toe-in and steering wheel centering. My cars track good and with no more miles than I average i don’t see any unusual wear. If I were rebuilding my suspension I would look into the Moog off set upper a-arm shafts.

 

Ron and Dan , i understand you both fully , but i cannot go "longer bolts" or ""offset upper arms shafts" as now i already had to dent primary 1 exhaust tube to clear the a arm bushing.

I have now 5x 1/8" shims at the rear bolt , which is max for clearance. I see enough thread for another two , but can't do it.

 

You just have to shim the front up and see what you can get. You may just have to compromise on how much neg camber and pos caster you can dial in and for regular touring it will probably be fine. If you need something more competitive then you may need to look at some aftermarket upper a-arms that have more caster built in.

 

Dan , i have it setup like that , 5 shims rear ( max ) , 2 front.

But must wait for P/S parts to finish that job , so i can test drive it. I trust camber/caster measurements only after driving it a bit so all can settle and i sure don't need to lift the front for the rotating tables. Just drive on them and measure.

 

You are right on readjusting after a drive. The rear Camber is the most difficult variable and seems it must be readjusted after a short drive. I had to correct it 3 or 4 times before it remained where I wanted it. I used two pieces of plastic with grease in a Zip-Loc bag for a table so the tires would move while adjusting with a bounce on the fender. Your tables should do better.