Komatsu 830E-AC Shop Manual page 626

Brake Caliper
Use only the specified components when servic-
ing the caliper. Do not mix components from
other calipers. If the wrong components are
installed, the caliper will not operate correctly
and can cause damage to the equipment. Use of
non Komatsu (OEM) parts can cause damage,
loss of braking and serious personal injury.
1. Position the housings onto a work surface so
that the cylinder bores are up.
2. Lubricate all cylinder bores, seals, backup
rings, piston seal surfaces and seal grooves
with silicone grease, such as Dow Corning
DC4. If this is not available, use the same
hydraulic fluid used in the brake system to lubri-
cate the parts.
3. Install a new piston O-ring into the groove of
each service piston bore. Push the O-rings to
the bottom of the grooves.
4. Install a new piston backup ring above each pis-
ton O-ring.
NOTE: Do not apply grease to the dust seals.
5. Install two new service piston dust seals into the
dust seal grooves of each caliper housing. Ver-
ify that the dust seals are fully seated.
6. Install a washer and new O-ring onto the
exposed part of each adjuster pin.
7. Lightly apply silicone grease to the four service
piston assemblies and adjuster pin O-rings.
Inspect the outside diameter of each service pis-
ton for nicks, scratches, surface roughness or
other defects. Replace service pistons having
any of these defects.
J6-22
8. Install the four service pistons (1, Figure 6-27)
1. Piston Assembly
9. Install a lock washer and locknut onto each pis-
When tightening the nuts, avoid turning the
adjuster pins. This can cause damage to the O-
ring and cause the seal to leak.
10. Hold the adjuster pin using a 5/32-inch Allen
11. Place each housing subassembly onto the
Armature Speed Rear Disc Brakes
into the piston bores of each caliper housing.
Seat each piston evenly around each O-ring,
and with even pressure, push the piston
through the O-ring and backup ring. Prevent the
piston from cocking in the bore. Verify that the
piston pin is aligned with its hole in the housing.
FIGURE 6-27. SERVICE PISTONS
2. Dust Seal
ton pin.
wrench and tighten the nuts to 13.6-17.00 N·m
(120-150 in. lb).
arbor press, and press the piston subassem-
blies into their cavities to the maximum
retracted position. Re-tighten adjuster pin nuts
as described in Step 10.
10/06 J06025