I just replaced the rear calipers on my '95 Maxima with rebuilt units.  They
came from different vendors, but both were "loaded" ... i.e.; everything I
needed to replace (except brake fluid) was supplied.  I didn't need the
extra stuff, as I had already bought Nissan pads and clip sets but it was
not an option.

The Nissan hardware included inner and outer shims.  There was trace
evidence of shims in the original setup, but they had mostly rusted away.
I installed new shims from the Nissan kit.

Neither rebuilt caliper included shims - just the upper/lower clips for the
torque member and the anti-rattle thingy that fits into the caliper.

Question: What are the shims supposed to do?  What badness happens when they
disappear?

Roby