Here's a tiny tutorial about what to look for when checking your pinion angle and you're sort of stuck using factory rear upper control arms. Ok, nobody is ever stuck with them, but if you have a car you want to restore and need to adjust it slightly, you can if you can get hold of the UCA variants. Agreed, it's a whole lot easier to get adjustables, but again, this is about something few people probably knew about. It was something I didn't know about until the mid-90s when I went to buy new control arms at the dealership. The parts dude told me that I needed to specify which rear UCA I needed. I'm like, Wut? He said they come in 3 flavors, 0, -1.5 deg, and +1.5 deg. He told me (unverified) that the 0 offset was the common and most-used arm, but they did have some for slight adjustments to the pinion angle if needed. He said it was done by where the rear mounting hole position was placed changing the effective length. Again, unverified, but it's the only way it could work. Obviously, the idea was the -1.5 would push the pinion shaft down 1.5 degrees (longer distance between centers), and the +1.5 would pull the pinion shaft up (shorter distance between centers). And they need to be bought in matched pairs. Or if you just buy one, needs to be matched with the other on the car.
It won't solve every pinion angle issue you may have, if you need a different amount of pinion adjustment. Remember these are compromised engineering solutions for factory junk. Not much adjustment, but they did have a method available if needed. There should be a stamped two-letter code on one side of the rear UCA's. It's either XR, XY, or XZ.
XR equates to zero offset. P/N 10000076. These are the ones I bought because I've yet to get up underneath to check mine. If I found out they're not 0 offset, I'll just rebush the existing ones. Sorry, no picture.
XY equates to -1.5 degree offset. P/N 10001059. You can see the XY stamp here.
XZ equates to +1.5 degree offset. P/N 10001060. You can see the XZ stamp in the pic.
It won't solve every pinion angle issue you may have, if you need a different amount of pinion adjustment. Remember these are compromised engineering solutions for factory junk. Not much adjustment, but they did have a method available if needed. There should be a stamped two-letter code on one side of the rear UCA's. It's either XR, XY, or XZ.
XR equates to zero offset. P/N 10000076. These are the ones I bought because I've yet to get up underneath to check mine. If I found out they're not 0 offset, I'll just rebush the existing ones. Sorry, no picture.
XY equates to -1.5 degree offset. P/N 10001059. You can see the XY stamp here.
XZ equates to +1.5 degree offset. P/N 10001060. You can see the XZ stamp in the pic.
