Hi all.
ive recently undergone the task of removing the irs to replace trailing arm bushings, breakpads and rotors (and probably diff fluid while all is removed.)
Anyways my main concern with this project is the rear end alignment. for as long as ive had the car the rear passenger side (U.S.) camber has been badly out of spec (last measurements before dropping the irs was -1.8 degrees as compared to the acceptable -.5 to -1.0 range.)
now that ive gotten to the rotors ive noticed the passenger side has several more shims at the rotors as compared to the drivers side.
i guess my question is do these shims impact the camber?
and if so how do i go about replacing the rotors and ensuring i have to correct amount of shims?
most of what ive seen people say to put everything exactly back as it was and it should be correct. is there any way of checking this before putting the whole IRS back in?
I have very little knowledge of alignment adjustments so this will be a first, please bear with me.

 

The shims on the inboard flange of the driveshafts do indeed control the rear camber. Removing shims INCREASES negative camber; adding shims DECREASES negative camber. So ifyou have too much negative camber, add some shims. BUT, it is important to rebuild everything first as such things as disc thickness affects camber just as shims do, and any bearing wear in the lower wishbone fulcrums also.

After rebuild, when all is complete including shocks, brakes etc, before installation, my advice is to set up the driver's side as it is now as far as camber shims are concerned. Then, turn the axle on its back and measure the camber angle on the wheel flange. Does not matter what the angle is; then adjust the passenger side shims to give you the same value. This should give a decent starting point.

Then install in the car and remeasure with blocks under the hubs (watch out or the grease nipples!) let the weight of the car onto the axle and adjust if needed. For good handling abour 0.75° of negative camber is perfect. Use one of this sort of thing to do the measuring:

 

Gotcha, ive understood most of that except the part in reference to turning the axle on its back. do you mean to flip the entire irs so that the face of the differential (plate that connects to drive shaft) is pointed in the air?

ive picked up a set of calipers today so i can get measurements for the old rotors and new as well as what size shims and how many are already in there. hopefully providing those numbers as well as my last alignment will also be helpful in determining what shims i need.
once ive got those numbers all together ill post them here and see what people think.

my only fear is that during my last alignment my rear passenger wheel hub was not mounted properly and i can only assume this also had some impact (if not making the entire measurement null) and therefore i truly wont know what i need to do until its all mounted back in the car.

 

Gotcha, ive understood most of that except the part in reference to turning the axle on its back. do you mean to flip the entire irs so that the face of the differential (plate that connects to drive shaft) is pointed in the air?
YES

my only fear is that during my last alignment my rear passenger wheel hub was not mounted properly and i can only assume this also had some impact (if not making the entire measurement null).
Please explain this better. It is best to measure rear camber using the actual hub flange, wheel removed, weight on the hub which needs a thick block under it to ensure the car does not ground.

therefore i truly wont know what i need to do until its all mounted back in the car. That is why getting a starting point axle off car (see my post) is a good plan.

 

okay gotcha that cleared some things up for me.
ignore my end ramblng about the measurements and stuff now that ive grasped the concept about copying the angle from the good side a bit better i realize thats sort of irrelevant.
gonna get started cleaning painting and reassembling hopefully is smoother sailing from here
appreciate the help greg youve given me a bit more confidence in getting this thing back together correctly

 

Good luck! On the dog bones, I pretty much followed Grant. Anything to be done to the diff/cage fixings MUST be done first. Cage upside down plus a helper is best. In detail, having rebuilt the inner bearings of the lower wishbone, I loosely attached the dog bones, assembled the fulcrum pins into the wishbone/cage/dogbone lineup, so everything was there but the dog bones were not solidly attached, and did up the pin-end nuts, BOTH sides. The loose dogbones make it easy to install the pin. If the cage splays open, a ratchet strap or large clamp can help align it.

Then I measured the dogbone to diff gap under each bolt with some feeler gauges and made up shims to the required depth under each of the bolts, four packs all different very likely.
Then retract ONE side's pin enough to get on the bolts, install the shims, then you MUST use high strength Loctite, the sort that needs heat to undo, and do up the bolts tight.At this final stage do NOT forget the spacer tube after inserting the pin through the first bearing. Do up the pins bolts. Then do the other side.

This procedure worked really well. But a helper makes it all far easier when getting everything positioned and lined up, and the many bits of the bearing assemblies prevented from dropping out etc etc.

 

Pardon my sophomoric recommendation; you are probably on top of this already. But now is the time to address the Parking Brakes and mechanism too.

 

^^^
Sometimes the most "obvious" and "simple" things are completely overlooked in the rush to get to the "Fun Stuff."
(';').