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The Leaning Mustang Club

(name given by MFE)


When I purchased my 90GT, I noticed that the car sat higher on the rear passenger side than on the rear driver's side.  I figured that the problem must have been a worn suspension component, and since the plans for this car have always been to make it open track ready with all Griggs Racing components, I figured through the course of my upgrading that I would figure out the problem as I replaced factory components.  I wish it had been so easy.  A freind of mine locally has a 90GT as well, and his car has the same lean as the one pictured below.  I soon found out through message boards that these two instances are not isolated.  There are many that are experiencing this same problem, which has been elusive as of yet.

Here is a picture of the car from the rear taken 4/28/02:

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(I had to make the picture wide, because if I had just cropped the picture right around the vehicle with no referencing background, the lean was harder to pick up.  In person, the lean is easily recognizable.)


The obvious lean can be observed a number of different ways:

First, you can look at the car from the rear while it is on flat ground, and obviously it sits lower on the driver's side.  You can look at the car from the front and notice the same. 

You can look at the car from the driver's side and measure the fender lip to the top of the tires, then go around to the passenger side and do the same and notice that there is about 1-1/2" more space in the rear and 3/4" more space in the front on that side.  It does not take a tape measure to be able to discern that there is a difference, it is very visible to the naked eye.

You can sit in the car and drive it down the road and notice that you, in the driver's seat, are sitting lower than the passenger, even when the road slopes to the passenger side a pretty good deal.

You can park the car on a stretch of ground that slopes slightly to the driver's side (just very slightly) and the gap in the passenger rear increases much more than the incline shoud produce.  On a stretch of ground that slopes to the passenger side, the condition corrects itself a little, but not nearly to the same degree.

If you drive around a right turn (which normally would produce a little bit of body roll to the driver's side) a huge amount of body roll is encountered.  Conversely, when you go around a left turn (which should produce the same amount of body roll as the right turn only to the passenger side) the car stays much flatter than when into the right turn.

If you look underneath the vehicle, you'll notice that the body and the axle tubes are not parallel.  This causes the top of the passenger side rear tire to sit closer to the edge of the fender (horizontally) than the driver's side.

And the final way to observe the lean is to be the lead car in a group of cars, and have every one of your freinds ask you what is wrong with your car.  Then they say "don't you think it is time for a new car" since your car looks like it has a disease. 


The Steps I've Taken to Correct This Problem, So Far to No Avail:

1.  Coil Springs and Coil Spring Isolators:

My first thoughts were that the factory springs must be sagging and/or the factory spring isolators were somehow messed up.  I replaced the springs with FMS "C" springs and Energy Suspension coil spring isolators front and rear.   Installation of these items produced no improvement, and in fact, since the car was now much lower in the front (raked,) the passenger side ass end was sitting even higher in relation to the driver's side than it had before.  Also, it was now noticeable that the passenger side front sat higher than the driver's side as well.  I did not replace the factory struts and shocks at this time.

2.  Rear Shocks:

I kind of figured that shocks were not the problem, but I bought two rear shocks and installed them anyways (I got two cheap ones from Advance Auto Parts.)  Sure enough, I installed these and there was no change.

3.  Complete 8.8 Rear End With New Axles:

I started thinking that the axles, axle tubes, control arm mounts, or shock mounts could play a role in this problem.  I decided I wanted steeper gears, so I did a rear end rebuild with a used housing that I checked for straightness before beginning.  At this time I installed the new rear end and there was no change in the leaning of the car.

4.  LCA's, UCA's, and Rear Sway Bar:

Still concentrating on the rear of the car, I decided to install Global West LCA's and FRPP HD UCA's thinking that one of the factory units had to be twisted or a bushing had to be worn, causing the rear to become other than parallel with the body.  It was also at this time that the thread "what if my car leans to one side" was started at, and someone mentioned the rear sway bar.   I figured since the rear sway bar's job was to keep the LCA's parallel in cornering, that a bent sway bar could very well be the culprit. 

Installation of these items caused no improvement whatsoever.  At this time I also "checked" the torque boxes.  Nothing was visibly broken, torn or ripped.   They appeared to be in good condition, although admittedly I have an untrained eye when it comes to torque boxes.

5.  Front Coilover Springs, Sway Bar Endlinks, Struts and Shocks:

At this point I had pretty much changed everything in the rear suspension.   Someone on the messageboards gave the thoughts that the problem was not in the rear, and that it had to be in the front but was more visible in the rear.  So my first step was to just see if leveling out the front end would cause the rear to sit level.  I placed a jack under the driver's front frame rail (which is behind the tire) and raised the car a little (to the point where the front fender gap was the same as the passenger side,) and to my surprise, the rear end appeared to be completely leveled out.

Since I was tired of having stock turbine wheels, I decided to do a low-buck 5 lug upgrade and run 95 Cobra R wheels.  I knew that these would not fit under the wheel wells if the car was not level in the front, so I decided at this time to install D&D's front coilover kit with Tokico Premium struts and shocks.

With the spring perches on the coilovers set even right and left, the car sat exactly the same as it had prior (which ruled out front struts as being the problem.)  Next I adjusted the spring perches so that the driver's side was 1" higher than the passenger side.  This did give me the same vertical fender gap on both sides.   When I walked around to the rear, though, it was obvious that the condition was not solved.  There was a miniscule improvement, but the rear stance is still ugly. 


Some Measurements:

This afternoon I took some measurements and some pictures of this problem.  These were taken 4/28/02, after the coilovers were adjusted in an attempt to level the front of the car out.

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Here is the front of the car as adjusted.  First look at the top of the headlights and compare them right to left.  I measured the two sides from the top of the headlight assembly to the ground, and the result was that they were dead even.  I did the same from the middle of the fender lip to the ground on each side, with the result being that they were dead even.  But notice the cowl area of the car.  It sits visibly lower on the driver's side than on the passenger side.  I backed this up with a measurement as well, and the result was that the driver's side from the cowl area (actually measuremed at the start of the door) was 3/4" lower than the passenger side.  Notice the roof also is tilted to the driver's side.  I measured this as well (from the middle of the door at the top to the ground, the result was the driver's side was 1" lower than the passenger side. 

For the life of me I can not explain how the fender lip to the ground measurements could be dead even, and then behind that the measurements are not other that to think that this car has to be twisted up.  Obviously, if I did not have the coilovers adjusted, the whole car would be leaning to the right, including at the fenders, so this makes the problem even more elusive to me.  Could I have twisted the car up just by adjusting the ride height at the corner?  Could be, but if so, what the hell would that mean?   I have no idea but I'll keep working at that.


Here are the pictures of my fender well gap measurements, again, after adjusting the coilovers to compensate for the lean in the front.

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Front driver's side - 3" to my reference point on the tire.


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Front passenger side - 3" to my reference point on the tire.


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Driver's side rear - 2 3/4" to the reference point on the tire.


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Passenger side rear - 4" to the reference point on the tire. 


Now before anybody says "1 1/4" doesn't make a difference, just live with it" let me say that in person it looks ridiculous, not to mention the body roll in turns being dramatically different right to left.


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The passenger side.  Notice the gap in the rear.


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Driver's side.  Notice the front fender gaps are the same, which I adjusted "artificially."  Then notice the rear gap, much smaller than the passenger side.  Also remember that the difference in the rear would have been worse in the picture if I hadn't adjusted the front coilovers to level them out.


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And here is the vew from the inside.  Notice the dash and cowl area leaning down to the left.


I took one other set of measurements - from the frame rails to the ground.  In the front, the frame rails were dead even, at 8" off the ground.  In the rear, the frame rails were 1" off, at 8" to the ground driver's side and 9" to the ground passenger side (I might have those last measurements incorrect, but the difference, 1", is the same.)


So What Now?

I have lots of ideas, but less time, so this is moving slower than I would like.  The plans for the car, as I've said before, are to have a Griggs GR-40 suspension.  But this Griggs suspension requires a lot of welding (including subframe connectors) and I don't feel comfortable in the least welding on this car when it has a problem that could be structural. 

So here are my future plans in regards to this leaning problem, which has to be fixed:

A.  Take the car to a frame shop and have them put it on a rack and tell me if the car is straight or not. 

B.  Purchase coilovers or weight jacker type control arms for the rear and rig it up some more (I don't like this idea.)

C.  Replace the front lower control arm bushings (a shot in the dark, but part of the GR-40 suspension anyways.)

D.  Cut the rear coil springs (again, I don't like this idea.)

E.  Replace the tubular K-frame (another shot in the dark, but also part of the GR-40 suspension.)

F.  Weld subframes and Griggs through the floor frame kit into place after I've artificially leveled the frame rails to the ground (kind of scary.)

G.  Replace the motor mounts, which are worn and causing the fan blade to contact the fan shroud.

H.  Have the car corner weighted and see if this is a weight distribution problem.

I.  Change the front sway bar (or at the very least the bushings.)

J.  Become a little bitch like a few others that have responded to the thread on the corral and say "this thread is really long, you are never going to find the problem, just live with it."

K.  Buy a 2002 Camaro SS.


That is about all I can think of to do.  Some people have mentioned "factory tolerances" as the root of this problem.  To them I say first, no one would accept a new car from a dealership in this condition, so it isn't possible that it came this way from the factory.  And second, if it were possible, it still handles and looks like shit so I'll just have to learn how to fix the factory tolerance problem. 


If you are having this same problem, you know where I'm coming from when I say that this sucks big time cock.  Continue to follow this webpage and follow the "what if my car leans" thread at

If you have any ideas that you think might be the worthwhile to check, or even better yet, if you've fixed your similar problem, please either email me at, PM me at (5.0cpa is my username,) or post in the "what if my car leans" thread at   Any suggestions are appreciated, as there is no stupid suggestion seeing as how everything is suspect just like on that movie "Scream" of which I sat through for 2 hours and can't even remember getting to see naked breasts. 

And finally, don't give up on this because it is only a car.   If something is wrong with it, it can be fixed.  Everything can be fixed.   How hard or elusive it is will be a different story.