ChrisCoaster wrote:
>
> I recently upgraded to H-rated tires of OEM size for my Impala and had
> 4whl alignment done as a package at a local Town Fair.
>
> The improvement from S-rated to H-rated was noticeable, particularly in
> steering response. No more squeal in turns, and a firmer ride.
> Unfortunately, the car "seemed" to exhibit some pull to the left, which
> I brought the car back for the next week.
>
> My sales rep reviewed the alignment printout which showed everything to
> be pretty much within manufacturer's spec window, but proceeded to rack
> up my car for an adjustment. And actually, the conditions that would
> contribute to a left-pull: more positive camber on the left, less
> positive caster on the left, were not the case!
>
> Afterwards, I was handed a new print out, which showed my caster to be
> just outside the manufacturer's window, but all other measurements
> within spec. Caster for the '03 Impala should be +2.7 <> +3.7 deg, but
> mine was +2.5L/+2.6R. I asked how the caster got to be so out of spec
> and will it effect my driveablity, the sales guy said, the other
> adjustments affect caster, and, no, it shouldn't effect driveablity.
>
> Once back on the road, the left pull was gone, but now the car exhibits
> little or no "center" feel to it. Steering wheel return after a turn
> is not nearly as nimble, and I often must correct slightly one I'm on
> the road I turned on to. And even at highway speeds, I have to guide
> the car to keep it in the lane I'm in.
>
> If what the sales rep said is true, what other adjustments can have an
> effect on the Impala caster, which itself is not adjustable? And what
> should I have them do to get the caster closer to GM's +3.2 suggested
> spec?
>
> Thanks in advance,
>
> -ChrisCoaster

Sounds like castor or toe is out of specs. Have an alignment done
by a reputable shop.
BTW, what is a "sales rep"? Is he/she/it ASE suspension and steering
certified?