embarrassing to admit..but today is the first time I noticed I have wheel spacers on the back wheels..
I've never done a brake job on the rear discs so I never paid attention to the rotors until today when one of the spacers "fell away" from the rotor.
I'm assuming they are factory?
I've been hunting a drive train vibration for the last couple of years and the spacers where pretty grungy. I cleaned them up with some 40 grit on my die grinder and put them back.
I'm hoping that was the cause.
my question..why would they install them at the factory instead of making the back spacing and off set correct.

 

Yes, they're factory; they're about 1/16" thick, made of stamped, cad-plated steel. You'll find them only on the rear wheels, and AFAIK, installed after-the fact to insure clearance around the rear suspension parts. They're shown in the factory shop manual, but I don't recall reading an explanation in there of why they are used.

 

The factory rear spacers were used with the steel drums as the optional (and I believe recalled) Aluminum drums are thicker, as well as the rear disks. They used the spacers to avoid having to have different axle lengths based on the different brake options.

I've ran it with and without the spacers without any contact issues. Also make sure you put them on in the right direction, if you put them on reversed they will not sit flat.

 

thanks for the explanation folks. the spacers were clearly marked in regards to how to put them on for dumbasses like me.