Komatsu 830E-AC Shop Manual page 618

Shoes, Linings and End Plates
To help prevent abnormal lining wear, replace worn,
bent or cracked end plates and distorted shoes.
Inspect the end plate cap screws for wear. Replace
the bolts if worn.
NOTE: End plate cap screws are highly stressed.
Inspect linings
1. Lining Wear. Replace the linings when the
thickness of the lining is less than 3.2 mm
(0.125 in.) from the back plate.
2. Lining Wear Not Even. Replace the linings if the
thickness of the two linings is significantly differ-
ent. Check the pistons for correct operation.
Replace the piston and/or housing if a piston is
cocked in the bore. Check that the disc surface
is flat and parallel to the linings.
3. Oil or Grease on the Linings. Replace the lin-
ings.
Always replace both linings. If only one lining is
replaced, possible disc damage can occur.
4. Cracks on the Linings. Replace linings that
have larger or deeper cracks than the small,
tight cracks on the surface of the lining which
are normal when the caliper is used under high
temperature conditions. These cracks are
referred to as heat check cracks.
J6-14
PISTON ASSEMBLY RETURN SPRING
FORCE AND BUILT-IN CLEARANCE (BIC)
1. Place the piston subassembly onto a spring
2. Set a dial indicator between the spring tester
3. Lower the spring tester arbor to compress the
1. Arbor Of Spring Tester
2. Special Sleeve A
3. Dial Indicator
4. Return Spring
Armature Speed Rear Disc Brakes
tester table. Install a special sleeve (2, Figure 6-
17) over the exposed adjuster pin (6).
arbor and table. Use a dial indicator with a total
range of 2.54-3.1 mm (0.100-0.125 in.) such as
Federal Mod C6K or C71, or equivalent, having
a ± 0.508 or 0.635 mm (± 0.020 or 0.025 in.)
scale with 0.0127 mm (0.0005 in.) increments.
spring to minimum height (7, Figure 6-17). The
indicator pointer will stop rotating.
FIGURE 6-17. SPRING TESTER SETUP
5. Spring Tester Table
6. Adjuster Pin
7. 1.40-1.65 mm (BIC)
(0.055-0.65 in.
10/06 J06025