A while back I rebuilt my disc brakes ('86 wagon):
- Took the calipers apart, Evapo-rusted away some rust inside, engine-enamal baked, then used the blue-green tube of Ate Bremszylinder-Paste to lightly coat all of the inside and the rubber. The rubber appears reconditioned.
- The pistons (one steel, the other resin) move smoothly and quite easily by hand (no leaks).
- Also lightly coated the rubber tubes that fit through the calipers and contain the guides' plastic sheeting that the metal guides slide on.
- Very very lightly - barely - coated the metal guides themselves. The calipers slide so very easily and perfectly smoothly - better than any calipers I've ever seen on any vehicle.
- Wagner over-bore master cylinder
- Wagner rotors & pads (same as I've used before)
Reporting the Driving Result: amazing braking force and even more amazing brake response.
Never dreamed I'd be driving a vehicle with such great brakes!
Brake applies with minimal force.
Extremely fine adjustment in brake pressure possible with seemingly instant response/recovery.
Reminds me of the brakes on my sister's RX7, only smoother.
Problem is, with changing at the same time to an over-bore master and to using the Bremsyzylinder-Paste, I don't know which is responsible for the improvement.
I assume that the over-bore master is the major contributor to a greater braking force, with the paste largely responsible for the finer adjustment and response due to a much lower piston resistance providing faster & finer (lower break force & no slip-stick) piston movement.
p.s. even with the stock pad clips, I frequently had a lot of noise from the pads jumping around. I found on highways I could use left-foot to apply a little brake force while driving to get the pads to settle into place, but they'd only stay there until the next turn, even if gentle. Applied gasket goo to the back of both inner and outer pads, assembled while wet and applied brakes, and the noise is gone since.