Rear Alignment Problems, Shifted Subframe?
May 12, 2014, 10:09 AM
#1
Rear Alignment Problems, Shifted Subframe?
The passenger rear is AS GOOD AS IT GETS. Those numbers are with the camber eccentric MAXED negative, and the toe eccentric binds and won't go further toward zero. Now, here's the kicker; the camber eccentric on the driver's side is maxed POSITIVE. It will not go any more positive than -0.8. Toe is fine on that side. So I've come to the conclusion that the subframe is out of alignment with the unibody seeing as the numbers and bolt positions point that way. Only explanation I can come up with as to why it would be like it is considering the unibody, as far as I can tell, is straight (only one minor accident, everything lines up, etc).
Anyone seen this before? Am I thinking crazy or on the right track?
May 12, 2014, 10:17 AM
#3
That toe on the right rear will definitely start wearing the tire out. By "only one minor accident"...What happened? Hit a curb with the back right rim? Check where the control/trailing/toe arms bolt to the body. Have those areas been "massaged" at all?
May 12, 2014, 02:21 PM
#4
Car has Apexi N1 EXV coilovers, which are in fine shape to my knowledge (3k on them over a couple years, only saw salt a handful of times), and there is no play anywhere that I found. The fact that the issue is inversed from side to side tells me it's not simply a bad bushing or joint.
It was backed over a curb at like 50mph in the wet, but is was on a cloverleaf, so not a 90 degree curb, like a 40 or so, nothing that would have really damaged anything. It spun a full 180 as it went off, but how it went over that I do not know. The damage was all cosmetic, a tree branch took out the wing, there was damage to the passenger doors and rear quarter. The car drove out of the ditch and 30 miles home without issue.
The one caveat is that the car did make 1000hp for 3k during its time with the 2nd owner, right up to when he parted it out and sold the shell to #3, who didn't align it but in the process of rebuilding it never mentioned anything interesting. But that doesn't mean the power couldn't have moved things around.
May 13, 2014, 10:13 AM
#7
I've had similar experiences on the alignment rack. turns out the car shifted on the rack while they were adjusting the front suspension and messed up the calibration of the rack. try taking it back in and starting over with the rear end first. I bet your baseline measurements won't match what you've got there.
second guess is that your rear ride heights aren't equal, which can screw with the geometry. I'd guess that is less likely though.
second guess is that your rear ride heights aren't equal, which can screw with the geometry. I'd guess that is less likely though.
Trending Topics
May 19, 2014, 06:27 AM
#10
Evolved Member
iTrader: (11)
Join Date: Oct 2005
Location: Chicago
Posts: 4,165
Likes: 0
Received 0 Likes
on
0 Posts
Does the car have a bump steer correction kit? They can act like another set of eccentrics if you don't keep after them. Check those, and I would just go ahead and replace the adjustment bolts.
May 19, 2014, 09:03 PM
#11
Well, a buddy and I got the car up in the air this evening, and here is what we found:
The rear subframe looked to have shifted toward the driver's side, so we shifted it all the way to the passenger's side. Both sides are now at -0.5 for camber and about 1/4" toe in. This will do for now, and I still need to have the front end realigned to match it. The eccentrics on both sides are still way out of whack for how it's currently set though.
We took a ton of rough measurements on the arms and everything matched up on both sides. So at this point the next step is a frame rack.
The rear subframe looked to have shifted toward the driver's side, so we shifted it all the way to the passenger's side. Both sides are now at -0.5 for camber and about 1/4" toe in. This will do for now, and I still need to have the front end realigned to match it. The eccentrics on both sides are still way out of whack for how it's currently set though.
We took a ton of rough measurements on the arms and everything matched up on both sides. So at this point the next step is a frame rack.
May 24, 2014, 11:59 AM
#15
The camber arms have been suggested by a buddy as well, and really would resolve the issue, but I want to fix it right and take care of the frame. The car does dog track a bit and pull as a result, so once everything is as it should be I'd expect that to go away.