Manitowoc Grove RT770E Service Maintenance Manual page 294

UNDERCARRIAGE
8. Remove the pistons from the mounting plate side of the
housing. Push on the ends of the pistons to force them
out of the disc side of the housing. Refer to Figure 8-17.
9. Remove the dust seals from the housing.
10. Remove and discard the O-ring and the backup rings.
Refer to Figure 8-18.
O-Ring
Backup Ring
11. Inspect the ring grooves in the housing for scratches and
rust. Remove small scratches and rust with emery cloth.
Replace the housing if there are large scratches or large
amounts of rust. Refer to Caliper Parts, page 8-19 in this
section.
12. Inspect the pistons and the bores for scratches and rust.
Remove small scratches and rust with emery cloth.
Replace the components if they are worn or if there are
large scratches or large amounts of rust. Refer to
Caliper Parts, page 8-19 in this section.
8-18
Inspection
Periodic On-Vehicle
Inspect the caliper, linings, and disc for any damage.
Shoes, Linings, and End Plates
Wood Block
Remove the shoes and linings. To help prevent abnormal
lining wear, replace worn, bent, or cracked end plates and
distorted backing plates. Inspect end plate bolts for wear.
Replace the bolts if worn. Inspect the linings for:
Piston
FIGURE 8-17
FIGURE 8-18
NOTE:
Caliper for Leaks
Inspect the following areas for fluid leaks. Refer to
Figure 8-20.
Published 11/26/2014, Control # 447-05
• Lining Wear: Replace the linings when the thickness
of the lining is less than 0.125 in (3.2 mm) from the
back plate. Refer to Figure 8-19.
• Lining Wear Not Even: Replace the linings if the
thickness of the two linings is significantly different.
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. Refer to Figure 8-19.
Minimum Lining Thickness
0.125 in (3.2 mm) from
Backing Plate
Uneven Lining Wear
• Oil or Grease on Linings. Replace the linings.
• Cracks on Linings. Replace linings that have large
or deep cracks.
Small, tight cracks on the surface of the lining are
normal when the caliper is used under high
temperature conditions.
RT770E
FIGURE 8-19