I rebuilt my 73mm LSC calipers today. It wasn't too hard
a job, but does have a few steps of note.
**removal from car**
1.  Jack up the front of the car and place it on a pair of stands.
2.  Remove the road wheels.
3.  Clean the area around the caliper and the brake line feeding the
    caliper of dust and trash.
4.  Disconnect the brake line at the caliper.
5.  plug the brake line to keep the fluid from running all over.
6.  Remove the pins holding the brake pads.
7.  Move the calipers to a clean work area.
1.  Remove the pads from the caliper.
2.  Place a block of wood in the space where the pads were
---NOTE: keep fingers clear of this area!!---
3.  Using some air pressure, pressurize the caliper. This will FORCE
    the piston out of the bore....FAST & HARD. Count your fingers
    to ensure they are all still there. Repair any damage done to the
    hand prior to commencing.
4.  Remove the old dust boot and piston seal. Throw away.
5.  Examine the piston for damage. Replace if necessary.
---NOTE: clean. clean. clean. keep the area and calipers clean.----
1.  Clean everything completely. You can use brake fluid, or buy one
    of the commercial products designed for this.
2.  Install the new piston seal. Install the new dust boot on the caliper.
---NOTE: make sure the dust boot is completely seated in the groove
   in the caliper.---
3.  Apply some clean brake fluid to the piston seal.
4.  Fit the piston to the caliper area.
5.  Pull the dust boot up over the sides of the piston
6.  Place the caliper on a clean surface, back side to the ground.
7.  Center the piston on the bore. Use a piece of wood to go across
    the piston, and apply even pressure to both ends of the wood,
    gently forcing the piston into the bore.
           X push down                push down X
         |________________________________________|   <- wood
                    |                   |  <- piston
                    |                   |\
                    |                   | \   <- dust boot
     ------\ _______|___________________|__|_________ /--------
            /       .                   .            \
                    .   piston bore     .               <- caliper
8.  Seat the dust seal onto the piston.
9.  Reinstall and bleed brakes.