Alignment drift

[Cdaniel]

I've got a few thousand miles on a completely new stock front suspension in a 66 Fastback. It has new tires and was aligned at a reputable shop. I've recently noticed the camber is shifted to the negative on both wheels and is wearing the edges of the tires.

Any ideas what could cause this with all new parts? My 1st thought was shock towers but I have no cracks. Is the car possibly settling in after being on blocks for two years? Is a Monte Carlo bar in order?

 

[usedtobe 67p51d]

if it's true stock the camber is only adjustable via shims behind the upper a-arms, so yes add a monte-carlo bar

check your fateners after EVERYTIME someone works on your car...a shop that I trusted left my strut-rod adjusting nuts untightend...they didn't even run them up to the stops

on '67 and up cars the camber is adjusted by the excentrics that the lower a-arms bolt through If you drive the car hard you'ld walk the adjusters. at willowsprings I'ld start with 1/2 degree of negative on left and right and come home with something like 2 degrees poitive on the left and neg 3 on the right and that would be with proper torque on the fastners


I started welding the excentrics to combat this untill I stopped useing the ford stuff.....G-plus sells a square plate with four holes set at differant setbacks to get your choice of firm settings

 

[JB66]

It is VERY unlikely that the camber is your problem. It would take an extreme amount of camber to wear the edges of your tires. The problem is your toe setting and it's probably because they set it with the engine not running. I'm assuming you have p/s. The free play in the p/s control valve is not taken up unless the car is running.

 

[94CobraPace]

Yes the eccentric adjuster can wear out, move & cause the tires to lean & wear on the edges. When my 67 did this I too got the square block from S+, harder to align, but once done it will not move.

 

[Cdaniel]

It is VERY unlikely that the camber is your problem. It would take an extreme amount of camber to wear the edges of your tires. The problem is your toe setting and it's probably because they set it with the engine not running. I'm assuming you have p/s. The free play in the p/s control valve is not taken up unless the car is running.

Well the steering is manual but toe could be part of the problem. However there does seem to be visible negative camber on both tires when viewed from the front.

 

[JB66]

The Ford shop manual states that the combined camber difference between the two front tires should be no more than 1/2*, and 1/4* is preferred. If you can visibly see camber in your front wheels, something is seriously wrong. Specs. are -1/4* to +1 1/4* with +1/2* as the desired setting. Shim pack thickness should not exceed 9/16". Did your alignment shop give you a printout?

 

[Opentracker]

Well the steering is manual but toe could be part of the problem. However there does seem to be visible negative camber on both tires when viewed from the front.

Try rolling the car backward by hand on a flat surface, then look at it. It's most likely the toe setting has moved from a 1/8" toe-in to a no-toe or a toe-out setting. If it looks better after the car has been rolled backward, it's time for a alignment. We use 0 camber on both sides, 1.5 to 2.5 Pos. caster on both sides with 1/8" toe-in. It is important that the caster and camber setting is the same on both sides or the car won't drive right.



John

 

[HistoricMustang]

Tell us more about the shop that did the front end set up. The shim process is very time consuming but necessary to get the alignment correct. It took over an hour to get mine where it needed to be and I was standing there the entire time to make sure it was correct.

HistoricMustang
www.historicmustang.com

 

[Cdaniel]

The Ford shop manual states that the combined camber difference between the two front tires should be no more than 1/2*, and 1/4* is preferred. If you can visibly see camber in your front wheels, something is seriously wrong. Specs. are -1/4* to +1 1/4* with +1/2* as the desired setting. Shim pack thickness should not exceed 9/16". Did your alignment shop give you a printout?

The print out is as follows:
camber L-.10 / R-.10
caster L-2.00 / R-1.70
toe L+.05 / R+.06

The guy did spend a while working on it. I watched from the fish tank the whole time. Looked like he was competent and was making multiple measurements and adjustments.

 

[JB66]

Based on the caster readings, I'll assume it's a 6 cyl, because the v8 caster should be -1 to +1. Camber looks fine. Why did he set it to toe out, though? The specs. call for 1/8" to 3/8" toe-IN. Desired is 1/4" toe-in. That would be my guess as to the tire wear.

 

[Cdaniel]

Based on the caster readings, I'll assume it's a 6 cyl, because the v8 caster should be -1 to +1. Camber looks fine. Why did he set it to toe out, though? The specs. call for 1/8" to 3/8" toe-IN. Desired is 1/4" toe-in. That would be my guess as to the tire wear.

It's a 289, not a 6. I guess I'll have to dig out my shop manual and take it with for discussion this weekend.

 

[usedtobe 67p51d]

toe it in,it should help

 

[whwright]

I recently had a similar problem on a car (not a Mustang) that my son and I are working on. We completely rebuilt the suspension using stock-style bushings. After a few thousand miles, the upper control arm bushings were completely shot, and the tires had a visible lean to them. The tread was completely gone on the inside third of the tire.

We took it to an alignment shop and they basically said that the bushings we installed were junk. They had no other explanation why the bushings went bad so fast. We paid them to replace the bushings (because I was sick of messing with it) and realign everything (again). It has been fine since then.

Long story short: make sure that all the new parts you installed are still "new."

Wayne.