Rear end alignment

[R8er]

Hi folks, after I put my body on, we realized that my mustang 4 link suspension is off by 5/16". We loosened all the suspension bolts and tried to push it over but it went right back where it wanted to go after we tightened up and dropped the car. It's not real noticeable but the driver fender is a bit too close to the tire and there is a 1/4" difference between passenger and driver quad shock gaps. Is this a problem that can be fixed or do I just move the fender out a bit and continue with my life?

[skullandbones]

R8er,

If you mean move the body when you say "move my fender out", that is most likely what you will have to do. I wouldn't assume the suspension is wrong. Those frames are jig welded. I would find some reference points under the chassis and measure the suspension points. More than likely they will be very close to the same right to left sides. Remember that the body is a skin and does a lot of changing shape during the mounting process. If you have a MKIV you are probably going to have a much better time of getting the body adjusted right. The rocker panel mounts are adjustable where on my MKIII, they are not. It shouldn't take much effort to get that rear squared up so it is good. I don't think a 1/4 inch difference in the quad shocks is that bad. Make your suspension measurements first. If there is a discrepancy and control arms are not new, it could be a bent control arm from a wreck (donor?). The reason I say that is that most people don't use the quad shocks so I was assuming a donor build. Don't know what combination of suspension setup you are using. Of course, don't have your roll bar(s) in place or quick jack mounts on if you need to adjust the body right or left.

Good luck,

WEK.

[CraigS]

If your tire is not hitting either the fender or the frame, I'd move on. You could get adjustable upper control arms to center it but why bother, it is way within reason IMHO.

[R8er]

Ok thanks, yeah the control arms are from donor but not wrecked. The measurements I took were from the frame to the inner wheel rim.

[mikeinatlanta]

Align the rear suspension to the frame. Correct body position as needed only after the suspension alignment is correct. You most definitely do not want to alter suspension setup for the body.

[skullandbones]

One thing you can do that will verify if you have your diff in squarely is to take a straight piece of angle stock and run it along the 4 inch tubular chassis tube on both sides. Now measure the distance from the stock to the inside edge of the rear wheels front and back. You should be looking at 1/16th or 1/32nds if you can (like when you are measuring the diagonals on a frame when you are checking for alignment on a frame table after a crash or fabbing a frame from scratch). This will set you up for the next phase of alignment after you have verified the diff is perfectly perpendicular to the frame rails. There are many threads that show that process that helps get the front wheels positioned for initial alignment before go kart phase. I transitioned from a four link to a three link with Watt's link. The only thing I haven't done yet is to remove the quad shock bracket mounts on the LCAs to clean that up. When I do that, I will add spherical rod ends to make the LCAs adjustable and remove any remaining bind that exists in the system. So if you are driving with straight line launches and cruising you will be fine with the four link. The four link will bind up in the twisties (triangulated [ / \ ] design). Just food for thought.


Good luck,

WEK.