Komatsu 830E-AC Shop Manual page 627

12. Install a new smaller diameter 63.5 mm (2.5 in.)
parking piston backup rings (2, Figure 6-28) into
the ring groove of each caliper housing.
FIGURE 6-28. PISTON SEALS
1. O-Ring
NOTE: Position the O-rings into the grooves below
the backup rings so that the backup rings are closest
to the disc.
13. Lightly lubricate two new smaller diameter 63.5
mm (2.5 in.) parking piston O-rings (1) using sil-
icone grease. Install the O-rings into the O-ring
grooves of each caliper housing.
Inspect the outside surfaces and grooves of each
parking piston for nicks, scratches, surface
roughness or other defects. Replace parking pis-
tons having any of these defects.
J06025 10/06
2. Backup Ring
Armature Speed Rear Disc Brakes
14. Install a new larger diameter 127 mm (5 in.)
parking piston backup ring (2, Figure 6-29) into
the outer groove of each parking piston.
NOTE: Position the O-rings into the parking piston
grooves next to the backup rings so that the O-rings
are toward the smaller diameter of the parking piston
and the backup ring will be farthest from the disc.
15. Lightly lubricate two new larger diameter 127
mm (5 in.) parking piston O-rings (3) using sili-
cone grease. Install one O-ring into the O-ring
groove of each parking piston.
16. Lightly apply silicone grease to the outside sur-
faces of each parking piston.
NOTE: Seat the piston evenly around each O-ring
and with even pressure, push the piston through the
smaller diameter O-ring and backup ring into the
caliper housing bore. Prevent the piston from cocking
in the bore.
FIGURE 6-29. O-RING INSTALLATION
1. Parking Piston
2. Backup Ring
3. O-Ring
J6-23