After putting 18x10's and 285/40's on the rear, it's become apparent that axle is mis-aligned about 3/4" to the driver's side.

Does anyone know which way the body shifts with a 1" drop with from Roush springs in the rear? I'm thinking I might get lucky and avoid having to buy an adjustable panhard bar if the drop moves things the right way.

My luck will be it'll move to the left even more, but who knows -

Thanks for any info -

 

It has been commonly reported that the axle is offset from the factory, but typically it is about 3/8". Are you sure yours is 3/4? That seems like quite a lot. Did you measure it or is that an eyeball measurement? If it actually is off by 3/4" then I would seriously consider having a professional examine the car, that sounds like something is definatley wrong.

I couldn't tell you which way that lowering will shift the axle. When I installed my springs I did the adjustable panhard at the same time. It is a good upgrade for handling/traction reasons in addition to keeping the rear centered.

 

Why would the factory offset the axle alignment? I would think the straighter the better. Whats the science behind this one? Is it bad to have the rear axle aligned perfectly straight?

 

I have no idea why the axle might be offset from the factory. It may be that it's designed to sit straight when the car is loaded down with passeners? Or, it may be a case of simple variation in production? I don't know the how or why about it, I was simply noting that it was something that has been observed by many people on the forums.

a small offset, such as 1/4", seems pretty common. Mine was off by almost exactly 1/4" stock. However, I am pretty sure that being off by 3/4 is cause for concern.

 

Mine is about 1/4" off. That's not enough for ME to worry about though.

 

When you drop it the rear end will shift to the drivers side. You will need an adjustable panhard bar to correct the alignment.

 

+1

When i lowered my car it got about 3/4"-1" off Thnkfully i already purchased the Adj. Panhard.

Richard

 

Thanks for the info - since a drop shifts the axle to the driver's side, I'll definitely get an adjustable panhard bar when I get new springs. After measuring more precisely with a plumb-bob this morning, mine is shifted 9/16" to the driver's side already.

Thanks again.

 

I guess I'm bringing this one back from a few months ago.. I need answers, hopefully someone can help..

I have a long story that goes along, that has a lot of insight, so please bear w/ me..

All started 2-3 years ago... I had to get the rear diff rebuilt since the whirring was terrible. Turned out to be an axle seal went bad, and I lost all the fluid over the course of a few months..

Well, shop rebuilds the rear-diff, but incorrectly. It slightly damages my 3.73's but as long as my Eaton LSD is fine, I don't mind a little gear noise.. Problem is, ever since then, I've had the vibration coming from what seems to be the middle of the car..

Fast forward to last Fall. Since I was sick of the noise, and it seemed to get slightly worse, I brought it to a good friend who took a look.. He recommended U-Joints. initially, since he didn't really get dirty that day.. After swapping them, I notice the vibration is a little worse.. He gets back under the car w/ me, and sees the tranny mount is trash..

I replace it. Most of the vibration is gone, but it's still pretty bad from 50-85mph, then it goes away. Gear noise is still present, so I re-shimmed my rear-diff. Noise is still there...

So.... Recently, I got a bunch of money, and decided to do the right thing.. Replace my entire suspension. Well.. No dice.. STILL have vibration, and I think it's causing the pinion seal to separate from the housing, and I'm getting a little oil spray right about the diff..

I replaced the U/LCA's, Shocks/Struts, Rims/Tires, Tie-rod ends, brakes, wheel bearings, hardware etc.. I mean, the only things original about my car are the engine itself, driveshaft and the paint on the rear of the car...

So I searched for rear-axle alignment, to see if maybe that is off. How does one go about aligning a solid rear axle?? Is it all toe-in/caster adjustments??


Any help would be huge!!!



JT

 

Excactly,
Also Not sure if you did it yourself or had it done somewhere, but I have heard from a few sources that the panhard bar needs to be removed to facilitate lowering the car or with certain types and sizes of wheels, thus requiring an adjustable panhard.