I got my 92 aligned a few days ago and afterwards, looking at the paper they gave me, noticed something that has struck me as unusual. My rear camber is -.3 degrees on both sides. I know this is not adjustable and on solid axle cars is usually zero. With production tolerances, things can go a little one way or another but is this unusual? I haven't looked at this on solid axle cars before so I am unsure how often this happens . It seems to me like I have something of a unicorn as small amounts of negative camber for the rear are a good thing and just maybe I have gotten lucky. So, is this a really fortuitous and unusual thing or happens all the time?

 

-0.3° is ... not a wholehelluvalot.

Just the same, I'd be inclined to suspect that the axle tubes are loose in the pumpkin. That being one of the ways that rear ends of this general type fail the most often. The tubes are steel, and the pumpkin is cast iron; not a good welding situation. All the factory did to assemble them was, they jammed the tubes into the pumpkin, and there were 2 holes in the pumpkin, and they welded a "plug" into the holes. The plug weld almost inevitably breaks. When that happens, the tubes can do whatever they want, which is usually, take the path of least resistance. (surprise) Given the distribution of forces on that junction (tube to pumpkin), one of the most likely results is, exactly what you just measured. Another thing you might see is, if you measure the rear toe AFTER a hard acceleration with only very light braking afterwards, is toe IN; conversely, if you measure it after VERY HARD braking, there will be toe OUT. The tubes aren't firmly attached and can go wherever The Force(s) move them.

One of the other inevitable effects of the failure of the welds is, they leak fluid. If there is ANY sign of axle grease WHATSOEVER around there, you may be sure that your plug welds have cracked and broken, like everybody else's.

I've had some GM rears of this design where the tubes were SO LOOSE in the pumpkin that I could move them by hand. Needless to say there were also misc clunking and clicking noises that occurred mostly when hitting the brakes and then accelerating right afterwards and other such times. Another problem that can occur is water leaking INTO the rear. One such car I had, when the rear started howling and I thought I should check the fluid, when I popped off the cover, nothing but water came out. The grease had all escaped and when I launched my boat using that car the rear filled up with water instead. Everything inside was TRASHED needless to say.

Welcome to factory minimalism.

When you changed out your rear axle grease, as of course all good and knowledgeable used car purchasers do as part of their initial catching up on "deferred maintenance" as soon as possible after buying the car, what did the guts of it look like? How much fluid came out? What did it look like?

 

To echo what sofa said .3 degrees is within measurement error. If you are not experiencing symptoms to the likes of what he mentioned, I'd say you're fine. You can't "allign" these rears in the traditional sense, but you can center them if you have adjustable components (LCA's, panhard etc).

 

My Strange 12 bolt has -0.3 camber too.

 

Well, I was looking at this as some kind of lucky godsend where the factory tolerances happened to line up in my favor and give me a little bit of rear camber where there usually isn't any. But since this could be a problem, no I haven't noticed any fluid leaking from the axle where it meets the pumpkin. Also as luck would have it, the seal between the pumpkin and the back plate, not sure what it's called, was leaking so I got some "right stuff" and resealed it, changed the gear lube. Everything inside looked perfect other than the huge size of the pinion gear (that's a 2.73 joke).