Rear Brake Options - '83 Ur-Q

[johncorbishley <jcorbs@cablemichigan.com>]

My brakes started making an ugly grinding noise at the rear this week,
so I opened everything up last night.

Source of the noise :- the inside pad on the rear passenger side was
right down to the metal, while the other pad has plenty of material.
The driver side pads are both fine.

Other observations:

Guide Pin seals on both sides in good condition, but the pins are
corroded and full of gunge.  The caliper piston on the DRIVERS side is
very rusty, while that on the PASSENGER side looks fine (I haven't
opened them up yet, but the seals look OK).  Discs are both showing
signs of rust, with the side facing the worn out pad very pitted.  Hand
brake has been deteriorating for some time.  The car got new discs and
pads at "professional" shop about 30 months ago.

QUESTIONS:

Do I merely rebuild and replace as necessary, or is there a logical
upgrade given the number of bits that need replacing.

Best source for these bits?

Any ideas as to what caused the one pad to disintegrate, and what to
avoid in reconstruction?  Perhaps a maladjusted hand brake?

TIA

John Corbs
'83 Ur-Q
Traverse City, MI