No Negative Camber With Rear Bolt

[JD Erisman]

Alignment is a topic beaten to death and I’ve read as many threads as I can find here, as well as B Bodies Only and E Bodies Only. I’m struggling to figure out what is going on with my alignment.
‘67 Barracuda, new spindles when I converted to 11.75 discs up front. Upper control arms from a ‘74 Dart with discs. Lower control arms are stock. I also installed new upper and lower ball joints as well as all new control arm bushings. Strut arm bushings are also new. All of the bushings were stock rubber replacements and the upper control arm cam bolts are stock. I also installed new torsion bars, hub bearings, and rotors.
A local shop did the alignment, didn’t take but a few hundred miles for the front tires to show outside wear, driver side much worse. Also, the steering wheel had no “desire” to return to center on its own.
I live in a small community, only two places do alignments here. I prefer to try an alignment on my own before going to the second shop.
For my initial settings: Rear control arm bolts are all the way in, front bolts all the way out. This resulted in camber to be positive 1.4° on both sides of the car.
Regardless of which side of the car I work on, adjusting the rear bolt causes camber to only gain more positive. I cannot move the camber less than 1.4° positive, while trying to gain negative, with any re-positioning of the rear bolt.

The only way I can gain negative camber is to move the front bolt well towards the inside of the car, which allows the .5° negative camber I want. This results in the rear of the control arm all in and the front of the control arm nearly all in.
Both sides of the vehicle have identical results.

I have no idea of my caster as I have not bothered to go past setting the camber.
I feel as though I’m backwards here. Does anyone have any insight?
Thank you

 

[Kern Dog]

First, you may not know but there are two different types of strut rods. One has fine thread on the end near the radiator, the other has a coarse thread.

They are different in length by about 3/16" to 1/4". I'm not sure which one is shorter, the fine thread or coarse. If your car came with short strut rods and you installed the longer ones, your caster will be reduced. This is because the longer strut rod pushed the lower ball joint to the rear. Thicker strut rod bushings can do this too.
Secondly, you can gain negative camber by using washers between the lower ball joint and knuckle/spindle.

I have done this to 2 cars. A .090 thick washer made a difference of about 5/8 of a degree of negative camber.
Finally, the taller the car, the less caster you will be able to get. It is simply how the alignment curve is with these knuckle/spindles. See chart:

 

[CFD244]

Did you use the Moog off set upper control arm bushings?

 

[RustyRatRod]

Are you making your adjustments with the weight off the tires? Another point is, the rear bolt will mostly affect caster, because it its position relative to the ball joint. While it will affect camber some, it will have nowhere near the effect the front bolt does.

 

[JD Erisman]

Thanks for all of the replies, I appreciate everyone’s time.
I have heard of the course thread struts rods vs fine thread, mine are identical and both fine thread and I didn’t install new ones, they are the original. I have heard of using a washer on the lower ball joint but am hesitant to do that when most people seem able to adjust enough camber without resorting to using that method. I’m afraid that would creating stress elsewhere, since it’s not what the engineers originally designed, in the suspension geometry of a street driven vehicle.
I’m making the adjustments with the car on the ground, rolling and bouncing it after adjustments are made. It makes sense the rear wouldn’t adjust any negative camber into the tire but I thought that is the bolt adjusted to bring back negative camber once the front and rear bolts are in their initial settings. The only way I get any negative camber added is to adjust the front bolt which definitely seems to be adjusting caster in the wrong direction.
I didn’t use the offset bushings made by Moog, I only installed stock components.
This should be a relatively simple task but I have spent probably forty hours reading, watching videos, adjusting the bolts this way and that without getting anywhere.

 

[cudamark]

You need to get the camber set right regardless of how much caster you end up with. Just get as much caster as you're able with the camber within specs. Otherwise, I suggest getting the offset upper bushings to get more caster. Spacing the lower ball joint out would be a last resort IMO.

 

[72bluNblu]

Your initial setting with the front adjusters all the way out and the rear adjusters all the way in is correct for maximum positive caster.

If you have positive camber at that setting all you can do is move the front adjuster in, you have to move the ball joint closer to the frame to get negative camber (or move the bottom of the spindle out, but that has to be a spacer). Since the rear adjuster is all the way in already the only way to get negative camber is to sacrifice caster.

With standard UCA bushings this isn’t completely unusual. These cars were initially designed to have positive camber and negative caster, because of the bias ply tires. The adjustment range with factory bushings isn’t all that much, so you may not be able to get much positive caster with negative camber. It also depends A LOT on your ride height. If the car is sitting above factory ride height getting any negative camber will be tough.

My suggestion would be to confirm your ride height is no higher than the factory spec. If you keep the factory UCA bushings then set only very slightly negative camber, between 0 and -.25°, and see what you’ve got for caster. It’ll probably only be a degree or so positive. Depending on your tires and driving style that may be ok. Personally I would recommend at least installing the Moog K7103 offset UCA bushings (not as the directions say but for max caster). That way you should be able to have slightly negative camber and a couple degrees of positive caster. Again not awesome, but better than you’ve got now and probably fine depending on the use of the car.

The spacers between the lower ball joint and spindle are an option, they don’t hurt anything although obviously you’ll have to adjust the toe setting. A plain washer isn’t a good choice but something harder or HD would be ok, AndyF used to sell spacers for exactly that application.

 

[CFD244]

With the Moog off set bushings, I adjusted to -.25* camber and ended up with +4 caster in my '71 Demon. Rear arm is all the way in and I got my measurements adjusting the front arm only.

 

[JD Erisman]

Thanks to everyone for your responses, it’s all great information. At least now I don’t feel as though there was something I was doing wrong though I will be lowering the car, it sits a little higher than stock to add clearance for headers and a deep tranny pan. For now, until new offset bushings come in the mail, I’m going to put camber at or near zero and see where my caster is, if it drives OK I will leave it alone for now. Or I will get as much caster as possible, regardless of camber, and add the washers to the lower ball joint to gain some negative camber until offset bushings are in hand.
Thanks again for all of your help.