Komatsu 830E-AC Shop Manual page 633

BRAKE LINING
Replacement
Inspect brakes periodically for wear. Linings must be
replaced when lining material has been worn to a
minimum of 3.2 mm (0.125 in.). Use of linings
beyond this wear limit will result in a decrease of
braking action, and possible damage to disc.
When replacing linings, never mix new and used
linings in an assembly.
1. To change linings, refer to Caliper Removal in
this chapter.
2. Place the caliper on a suitable work bench.
Refer to Caliper Disassembly, and follow Steps
1-14 to remove the brake linings.
3. Inspect condition of brake caliper thoroughly
before installing linings.
a. Inspect for evidence of fluid leakage. If
present, brake must be removed for disas-
sembly, inspection and repair.
b. Inspect condition of dust shields. These
should be soft and pliable, and show no evi-
dence of hardening of material, rupture, etc.
c. Inspect condition of tubing and fittings. If
leakage is evident, correct or replace fittings
as necessary.
Do not rub or press dust shield directly over
sharp edge around piston cavity. This may cause
dust shields to be cut.
d. Wipe brake housing and lining retaining
plates clean before installation of new lin-
ings. If a petroleum base cleaning fluid is
used, such as diesel fuel, use sparingly on
dust shields and wipe dry after cleaning.
4. Squeeze the service pistons back into the bores
by using a special tool or a large C-clamp over
the piston and the back side of the caliper. Use
caution not to damage dust shields.
5. Refer to Caliper Assembly, Steps 19-35 to
install new brake linings.
6. Refer to Caliper Installation to install caliper on
truck.
J06025 10/06
BRAKE DISC
Inspection
Inspect brake discs for wear.
1. Place a straight edge across face of disc and
NOTE: The disc only needs to be replaced when 20
to 25% of the disc wear surface is worn below 22.3
mm (0.88 in.).
2. It may be difficult to use a straight edge on the
NOTE: When installing new linings to be used
against a worn disc, useful lining life will be
shortened by the depth of the disc wear, since the
lining must advance this additional distance before
braking force is effective. In addition, the uneven
wear on the disc face will accelerate lining wear.
FIGURE 6-37. REAR BRAKE DISC WEAR LIMITS
Armature Speed Rear Disc Brakes
measure from straight edge to worn face. The
disc must be replaced when this measurement
is 1.52 mm (0.06 in.) or more on either side of
the disc, or when the disc thickness is 22.3 mm
(0.88 in.) on the worn face (see NOTE). It may
be difficult to use a straight edge on the inner
surface of the disc, so a visual comparison may
be used with that of the outer surface. Normally,
wear will be the same on both sides. See Figure
6-37.
inner surface of the disc, so a visual compari-
son may be used with that of the outer surface.
Normally, wear will be the same on both sides.
J6-29