Help IRS swap into 03 GT one rear wheel is -3 degree out

[thatglockguy]

I just installed a 01 cobra irs into my 03 GT.
I rebuilt everything, prothane bushings, SPC cross axis, bearings and repaired torn boot.
When I installed this the driver side camber is OK, however the passenger rear wheel is -3 degrees and I can't adjust this any closer to zero. I unbolted everything on that side with no change. Can anyone help me and tell me how I can get the passenger wheel to zero camber.
Thanks Woody

 

[01yellercobra]

Are you sure the cradle isn't bent? There really isn't much to do in the way of camber adjustment. If all the bushings are good I'd check the mounting tabs.

 

[thatglockguy]

I got it used can't tell if the cradle is bent or not.
When you say mounting tabs, they looked ok
Any way to check the cradle?
Thanks Woody

 

[shurur]

Ftbr sells camber bolts with more adjustment..maybe that would help...dunno

Might also contact ftbr or mm for tech.
Would think you could cross measure mount points for square and maybe check it with a level.

 

[thatglockguy]

Yes, I am calling them tomorrow. I don't think it will work because I had removed the camber bolt and drew out the spindle to obtain zero and the cross axis bearing hole was outside the camber slot in the ucr.
I just can figure out why is this side so far out?

 

[Dave.O]

post a pic of how the oblong washer is clocked in the upper knuckle.
this would be the rearward facing side of the upper arm / spindle pick up point

 

[04TorchMach]

Yes, I am calling them tomorrow. I don't think it will work because I had removed the camber bolt and drew out the spindle to obtain zero and the cross axis bearing hole was outside the camber slot in the ucr.
I just can figure out why is this side so far out?

Is your halfshaft all the way into the rear dif?

 

[thatglockguy]

post a pic of how the oblong washer is clocked in the upper knuckle.
this would be the rearward facing side of the upper arm / spindle pick up point

Yes Dave I will do that and post tomorrow thanks

 

[thatglockguy]

Is your halfshaft all the way into the rear dif?

Hi Torch, I inserted until it snapped in the diff. At this point I will pull and reinsert.
BTW: I torqued down the shaft nut, but could that change the camber?
I have a camber device and it is reading - 3.0/ -2.5. When I rotate the spindle to change the toe the camber hardly changes as well as when I lift the the spindle. Many people on the net say that on an irs toe will affect the camber and when the wheel travels up and down. I am confused about this. I see little or no change is that normal?
I have H&R lowering springs on it and prothane spring isolators on the top and bottom, I am thinking of removing them on the top of the springs and index them. Will this affect camber?

Will the change in ride height change the camber?
Do I have it indexed wrong?
I have prothane uca and lca poly bushings in it.
SPC cross axis as well.
This is a pic of my irs

 

[01yellercobra]

Really dumb question.....are you taking the reading with the car on the tires or with the suspension drooped? If it's on the ground how level is the spot the car is on?

I'm pretty sure toe is affected by camber. I can't see how adjusting toe will affect camber. But I'm no expert. If the toe isn't changing through the travel then I'd say your bump steer is good.

Yes, changing ride height affects camber. You're placing the suspension at a different point in the travel arc. Camber will change a tad.

 

[thatglockguy]

There are no dumb questions only appreciation for help. I am no expert either.
I have read it tires on the ground, tire on jacked up off the ground, jacked up with tire off and with very little change in camber. I also adjusted toe, no change, I loosen bottom LCA bolts set it on the ground and no change.
I did measure the center axle to fender and on the problem side, right side, it was 15.1 inches high. On the driver side it measured 15.6, is this significant?

I did install prothane spring isolators on both springs top and bottom would this be the reason?
I also installed FTBR swaybar links, could this affect camber?

 

[thatglockguy]

I am about ready to slot some of the mounting tabs for the uca and lca and the lower spindle mounting hole on the lca. The lca lower spindle mount would be the easiest to slot. I can at that point correct the camber.

 

[thatglockguy]

Should i remove the irs and see if is level?

 

[52merc]

You talk about jacking the tires up and down. After jacking the tires up off the ground, are you doing something to let the tires move back out? When you lift the tire up with a jack, especially if the suspension sags any, the tire has a tendency to move inward due to the arc the LCA follows. When you set the tire back down it will not be resting in its normal position, but inward some. If you don't have slip plates, you then have to drive the car back and forth some to get the tires back in their normal position. Could this be causing some error in your measurements?

 

[FIREBALL]

Something is bent or ----and I have experienced the following, My car ride height with lowering springs was different on both sides when i first installed them (which does effect camber) it turned out the position of the spring (the way they are turned) was the problem, I had to re-position my springs so that they were equal on both sides. If you have the lower cut end of the spring positioned to the outside but the other side is positioned on the inside the ride heights and camber will be different on each side. So I position mine with both the cut ends in the same position (both outside or inside) and that cured my unequal ride height and camber differences. When ever you change springs or jack up the car , it needs to be drove a few miles to settle the springs before you retake measurements.

 

[01yellercobra]

When I was adjusting my coilovers I would roll the car back and forth a few times to get everything to settle. It was time consuming but I got my workout in.

 

[thatglockguy]

Thank you all for you assistance. You guys at this site are the only ones that have helped me. Thanks again.

This is what I am going to do:
1 Lower the irs and remove the H&R springs
2 Remove the thick poly isolators from the top of spring and replace it with the stock thin one
3 Check springs to see if the springs are the same height
4 Swap springs to see if the problem switches to the other wheel
5 I read MM installation guide and now know the proper spring indexing
6 MM states to increase ride height rotate the spring pigtail 180 degrees
7 Reinstall irs
8 Check to see if all is good after a ride down the street

I am going to do this after work today

I would like to say that I do not have a Cobra SVT just a GT with an IRS
Since this is such a great site with great members I will get a Terminator rather that the corvette
I was thinking about
Thanks to all love you cobras
Woody

 

[shurur]

since your are going back in....
Some folks do away with the prothane isos altogether.
they use the upper rubber isos and put 5/8 heater hose on the bottom pigtails.

I have the prothanes and they squeak like hell.

 

[FIREBALL]

What M M said about turning spring 180 is basically what I was referring to in my post #15, You dont need to swap springs just turn the 3 degree side 180. Im going back to stock rubber insulators because for me the prothane are a little too rough. Be sure to mark your springs for what position they are in before you remove.

 

[thatglockguy]

ok, this is what I found
I switched the springs around and changed the isolators and no change
I remove the half shaft and no change

From my many observations I could not see anything that was making this negative camber.
So, I removed the IRS, removed everything on the frame except the spindles, uca, lca.
I put the frame on a level surface and the results is:
Driver side fine .5 negative camber with positive adjust so I can get it passed zero
Passenger side is still negative 3 out. I moved it up and down and no change.
At this point looking at the IRS the lca, uca, and frame appear straight, but it is not.
Well that was a $1500 loss I rebuilt every single thing on that IRS.
I just now have to fine which of the four things left is doing this.
Thanks for all of you help, I will follow up on this.
For now the straight axle is back in and a waste of 6 days hard work.