tires and wheels Alignment Question (Caster)

[Cru Jones]

So, my car ('74) has been pulling to the right and my steering wheel points to the right a bit as well since I've had the car (currently about 3 months). It's not horrible, but enough to annoy you when you drive it.  I finally brought it to an alignment place and they did their best, but said the caster is off between the front wheels (2.2 deg + L vs 1.7 deg R). They couldn't adjust it. I did a bit of research and it seems as though this might be solved by adjusting the subframe. Am I correct in my research? Anyone else run into this before? Suspension is Bilstein Sports, lower springs (if they match the back then Eibach) & IE sway bar kit.

[M3M3M3]

there is no adjustment in the subframe.  caster is not adjustable.

 

how old are your control arm and thrust rod bushings?  they "place" the lower end of the strut.  if they are old/worn or not tq'd correctly they could cause the bottom of one strut being in a different position than the other.

 

or your car could be bent.

 

but...that small difference in caster shouldn't make much difference in the steering.  hopefully your steering wheel is now straight after the alignment was done.

[mikebontoft]

It should technically be the other way around. .5* greater on the right side to compensate for road crown.

[Cru Jones]

there is no adjustment in the subframe.  caster is not adjustable.

 

how old are your control arm and thrust rod bushings?  they "place" the lower end of the strut.  if they are old/worn or not tq'd correctly they could cause the bottom of one strut being in a different position than the other.

 

or your car could be bent.

 

but...that small difference in caster shouldn't make much difference in the steering.  hopefully your steering wheel is now straight after the alignment was done.

 

As far as I know they're in good shape. The prior owner replaced all the bushings at some point with IE bushings and I took it to a shop a little bit back and they said everything was good in terms of bushings etc. That said, I will jack it up at some point and take a look.

 

So what would you guys suggest? Should I take it to a frame place and have them sort this out or get camber/caster adjusters (like the K-Mac ones) to fix this?

 

Oh, the steering is better, but still not perfect.

[mikebontoft]

They replaced subframe bushings? May need to play with the subframe a bit then. It can get off without being noticeable... until you get it aligned.

[Cru Jones]

Oh, forgot to mention, the camber for my wheels differs a bit as well. The front L is - .3 deg vs R of -.5 deg. Also, in the box of spare parts was a single front strut mount (new), with an empty box for the other. Is it possible that the PO replace only one of the strut mounts and that the one he didn't replace is more wore out now and causing this? Just trying to sort out if the two are possibly correlated...

[mikebontoft]

It could be possible... but a camber difference of .2 is negligible.

[Cru Jones]

Ok, I spoke with a local reputable race suspension shop and they said that it's nothing to worry about. They said it's pretty common for the caster to be off a little and to not worry about it.

[mikebontoft]

Well fortunately caster is not a tire wearing angle. Are you doing any kind of racing though?

[Cru Jones]

Not racing, but plan to track the car. Their suggestion was to get more negative camber, which is something I plan to do. So, all good for now. Need to get some camber plates put in soon I think.

[mikebontoft]

I'd pay attention to caster there as well.... a higher caster will provide more stability at a higher speed, but hinder your ability to turn. Just think of those chopper motorcyles with the long forks. They can't turn for crap.

 

At the same time, think of how the wheels (casters) on a shopping cart act at a high rate of speed (downhill shopping carts anyone? lol).

Edited September 16, 2013 by mikebontoft

[Cru Jones]

Yeah, I'd feel more comfortable if they were closer. I wonder if putting in the fixed plates and making sure everything's torqued properly will help (fingers crossed).

[mikebontoft]

you could always slot the strut tower (mounting holes) towards the rear. Hell, they could do that during the alignment.