W126 front brake caliper repair questions

[donbryce]

Last year about this time the mechanic who safety inspected my car mentioned that one of my front caliper pistons was "sticking". I paid no attention at the time and continued to drive the car, which we use for occasional out of town trips and mostly as a second vehicle around town. I figured with this low mileage, the sticking caliper might not cause me any noticable issues, as the braking worked fine.
Well, I'm now getting a distinct shuddering, but not so I can feel it at the pedal, more like the whole suspension is shaking when brakes applied, especially at highway speeds.
So I pulled both front wheels and checked all 4 pistons by retracting them with a C clamp. The right side is OK, with very little wear on the pads, and they're worn evenly on both sides (ATE calipers BTW). The drivers side however has a barely worn pad on the outside and about 1/8" left on the inner pad. The inner piston can be retracted easily with the C clamp though. I noticed a small tear in the rubber sealing ring on this inner piston too. My thoughts are that water has gotten in and caused some rust to build up, making this piston "stick" so it won't retract normally (which is from the centrifugal force of the spinning rotor, right?).
I didn't check the runout on the rotors with a dial indicator, but spinning them manually they didn't look warped, and I think I'd feel it at the pedal if one was, right?
So what I want to do is remove the caliper, clean up the piston, and fix the tear in the rubber. Yeah I know a kit is cheap, but to where I live, it'll still cost me about $40.00 per side, and I'd like to disassemble first anyway to see how bad the damage is, as I might need a new caliper.
CAN I DISASSEMBLE THE CALIPER/PISTON, AND RE-USE THE SEALS IF IT IS FEASIBLE, OR DO I NEED A KIT? In other words, has anyone successfully reused those seals after cleaning up a piston and bore???