Post Suspension drop question

[celticfdguy]

I lowered my 2010 GT500 this weekend. I used Bilstein B6 Shocks/Struts, Steeda Sport Springs and a BMR Panhard Bar. The car drives amazing and sounds great. I know I need an alignment on the front of the car with camber bolts but I noticed on the rear of the car after dropping it today that the passenger side was slightly higher than the drivers side. I have a full tank of gas in the car. Before I take it all apart again what do you think would cause this? Could my garage floor be uneven? Or could I have installed the springs in a different position on one side compared to the other side? Or is this just normal? Really appreciate it as always

 

[HKusp]

It could be geometry with the panhard bar if it's not an adjustable one, also could be you need adjustable upper and lower control arms. When I bought mine, it was on coil-overs and it was too low and rode like a shopping cart. I raised it up by going back to FRPP lowering springs and Koni shocks and struts. After that, the rear was cocked to one side and I had to add the adjustable panhard bar and control arms to get it right along with the pinion angle.

 

[celticfdguy]

It could be geometry with the panhard bar if it's not an adjustable one, also could be you need adjustable upper and lower control arms. When I bought mine, it was on coil-overs and it was too low and rode like a shopping cart. I raised it up by going back to FRPP lowering springs and Koni shocks and struts. After that, the rear was cocked to one side and I had to add the adjustable panhard bar and control arms to get it right along with the pinion angle.

I have an adjustable panhard bar on my car. I thought I had it adjusted right lol But I am having a hard time figuring out a way to measure it on both sides to see if its even. When I had 20x9.5 wheels on the rear I did the hang a bolt from a string trick on each side and use a tape measure to measure the distance to the wheel. I am on 20x11 now and the rope hits the tire. How did you measure it to make sure it was even on each side?

 

[HKusp]

Basically the same thing. Measured the outside of the wheel to the top of the wheel well using a plumb line.

 

[ToddW702]

You may need to loosen all the control arm bolts while the weight of the car is on them and then re-tighten them. You can have this problem when tightening them while the suspension is hanging.


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[XP900]

If you did all that work you should have replaced the upper control arm and complete bracket too with an adjustable one ...like a Whiteline unit or BMR unit, mounting bracket too...the 2010 used a smaller unit but you can replace the entire assembly with a 2011 and up model year. If I remember right the mounting holes in the body are all the same size.
I also replaced my differential bushing because I saw tears in the rubber on one side of it once I had the arm out.....real PITA to get out bushing out.

Reason I bring this is is because I installed a one piece DS and the pinion angle was off quite a bit and my car is not lowered either. At 35K my differential pinion race made a scraping sound (as if I was braking) all the time. I ended up having to replace the pinion gear and race ,,,, and did all the bearings while I was in there. I added the adjustable upper control arm to get my pinion angle back to where it should have been in the first place...a lot of work to do all on jackstands. Not sure if the bad pinion angle caused my pinion gear and race to fail or me screwing around but if you lowered your car you really should have that angle checked.

 

[celticfdguy]

If you did all that work you should have replaced the upper control arm and complete bracket too with an adjustable one ...like a Whiteline unit or BMR unit, mounting bracket too...the 2010 used a smaller unit but you can replace the entire assembly with a 2011 and up model year. If I remember right the mounting holes in the body are all the same size.
I also replaced my differential bushing because I saw tears in the rubber on one side of it once I had the arm out.....real PITA to get out bushing out.

Reason I bring this is is because I installed a one piece DS and the pinion angle was off quite a bit and my car is not lowered either. At 35K my differential pinion race made a scraping sound (as if I was braking) all the time. I ended up having to replace the pinion gear and race ,,,, and did all the bearings while I was in there. I added the adjustable upper control arm to get my pinion angle back to where it should have been in the first place...a lot of work to do all on jackstands. Not sure if the bad pinion angle caused my pinion gear and race to fail or me screwing around but if you lowered your car you really should have that angle checked.

I did the same mod on my 2007 GT500, springs, shocks, struts and adj panhard bar and didn't have to install new arms or relocation brackets. I spoke to some local mustang shops and they said what you mentioned wouldn't be needed to ensure that the wheels are even on both sides. I have an alignment setup for next week for the front and rear. Hopefully it goes well without any issue.

 

[XP900]

The pinion angle won't affect side unevenness, the earlier responses should resolve that issue. However whenever you change the geometry (ride height) of the body you can affect the pinion angle since the rear axle (differential) may tend to rotate to compensate for the changes. Most ignore it unless there are issues afterwards but nowadays for $30 you can buy a small square magnetic digital level which you can use to easily calculate the pinion angle. In my case my angle was about 3 to 4 degrees out of spec so I used an adjustable upper control arm to pull in back into spec after changing my pinion gear.