Suzuki SY413 Service Manual page 1735

6) Insert piston into cylinder by hand and fit boot in boot groove
in piston.
7) To confirm that boot is fitted in its groove in cylinder properly,
pull piston out of cylinder a little but do not take it all out.
NOTE:
Boot's face "B" should be at the same level from cylin-
der's face "A" all around.
8) Insert piston into cylinder by hand.
9) Install piston boot retaining ring.
BRAKES 5-41