Check for bent suspension arms?
Rennlist Member
Joined: Sep 2007
Posts: 4,533
Likes: 840
From: Massachusetts
Originally Posted by Top-Gun
Thought I'd post a follow up now that I've had time to look at the issue more.
My conclusion is that as suggested, the rear subframe is not perfectly square to the car. I base this on a slightly longer left side wheelbase than the right side, with every adjustment set identically.
I believe the car has always been this way, and to partially compensate the front subframe components were installed to limit wheelbase difference, which limits caster on the left side as the upper coil over mount is fixed.
I pulled the entire left front suspension apart, inspected everything, and reinstalled the control arm mount as far forward and inboard at the front within the limits of existing play as I could. This gets me to 5.25 degrees max left caster vs 5.55 max right, so pretty close. I could move the transverse portion of the front subframe (installed dead center of adjustment) to balance the caster precisely, but this would make the wheel base difference worse by further lengthening the left side.
The car takes an alignment within all specs, rear KT eccentrics ended up pretty equal on both sides once it all settled. Rear camber eccentrics are a bit different side to side but I believe that's to be expected, especially if the subframe isn't perfectly square.
In the off season I will drop the rear subframe and install solid bushings, taking time to equalize the wheelbase when I reinstall.
In summary, as far as I can tell based on no damage, all original structural suspension parts, and factory cosmoline on all subframe fasteners, the car has been this way since day 1.
My conclusion is that as suggested, the rear subframe is not perfectly square to the car. I base this on a slightly longer left side wheelbase than the right side, with every adjustment set identically.
I believe the car has always been this way, and to partially compensate the front subframe components were installed to limit wheelbase difference, which limits caster on the left side as the upper coil over mount is fixed.
I pulled the entire left front suspension apart, inspected everything, and reinstalled the control arm mount as far forward and inboard at the front within the limits of existing play as I could. This gets me to 5.25 degrees max left caster vs 5.55 max right, so pretty close. I could move the transverse portion of the front subframe (installed dead center of adjustment) to balance the caster precisely, but this would make the wheel base difference worse by further lengthening the left side.
The car takes an alignment within all specs, rear KT eccentrics ended up pretty equal on both sides once it all settled. Rear camber eccentrics are a bit different side to side but I believe that's to be expected, especially if the subframe isn't perfectly square.
In the off season I will drop the rear subframe and install solid bushings, taking time to equalize the wheelbase when I reinstall.
In summary, as far as I can tell based on no damage, all original structural suspension parts, and factory cosmoline on all subframe fasteners, the car has been this way since day 1.
