b. Install shoulder stud (18) in insulator (19) and
9-6. Inspection and Repair
secure with set screw (20).
a. Clean all parts using a suitable solvent before
c. Install grease fitting (17), insert subassembled
inspecting for wear or damage.
hook-insulator assembly in hole in the bottom of sheave
b. Inspect grease fittings for wear or damage
block (5), and install thrust bearing (16) and round nut
threads and replace damaged grease fittings.
c. Inspect hook assembly (21, fig. 9-2) for a
d. Install bearings (7 and 12) in sheaves (8 and
indication of cracks. The magnetic particle
11). Block sheaves and spacers (6, 10, and 14) in
(Magnaflux) or other suitable crack testing inspection
position in sheave block (5) and press pin (3) through
method should be used. No cracks are permissible.
assembled sheave bearings and spacers. Install cotter
Also, inspect the hook for increase throat diameter or
bending, as compared with new hook. A 15 percent
e. Install cheek plates (2 and 22) and capscrews
increase in throat opening, or a 10 percent side bend is
considered adequate reason to replace the hook
f. Lubricate assembly with type GAA lubricant
before returning to service.
d. Inspect all threaded items for thread damage,
g. Make sure that all sheave bearings allow the
pins for distortion, cracks, excessive wear, and bearings
sheaves to turn freely. If a sheave binds on a sheave
for wear scoring, or visible signs of damage. Replace all
pin, the wire rope will drag through the sheave groove
and damage the sheave and wire.
E Inspect sheaves (8 and 11) for wear or signs of
h. Clean up rough or burred edges on sheaves
cracking. Repair or replace a damaged or worn sheave.
with a fine file.
f. Replace insulator (19) if signs of damage a
Refer to TM 5-3810-294-10 and install the hook
a. Install hook (21, fig. 9-2) in insulator (19).
Section IIl. REPAIR OF SHEAVES AND BOOM ROLLERS
the groove is only slightly wider than the cable that
passes over it. Worn or corrugated grooves chafe and
Sheaves provide low friction pivot points for load cable
wear cables. Grooves may be smoothed on a lathe if
movement. Boom rollers assist in guiding the cable and
corrugations are not too deep. Any cracks in the body
prevent friction contact with the boom. Sheaves vary in
should be welded, ground, and checked for warpage.
size and application, however, maintenance is similar for
all sheaves. The only possible repair that can be made
to boom rollers is to replace them when they are
Before sheaves are installed, the sheave shaft or pin
excessively worn or damaged.
should be cleaned of all corrosion and paint. The inside
of the bushing and the shaft should be coated with a thin
layer of lubricant. The lubrication fitting should be
9-10. Cleaning, Inspection, and Repair
properly positioned during installation. Make sure that all
Clean sheaves with cleaning solvent and wipe dry,
sheave bearings allow the sheaves to turn freely. If a
removing all old lubricant. Inspect hub bushing for
sheave binds on a sheave pin, the cable will drag
excessive wear and replace if necessary.
through the sheave groove and damage the sheave and
lubrication fitting and make sure that passages are open
and have been receiving adequate lubricant. Examine
the sheave groove for excessive wear. A properly
grooved sheave has smooth side walls and
Section IV. REPAIR OF CI DRAGLINE, AND CLAMSHELL BOOM
carefully; the magnetic particle (Magnaflux) method is
recommended. Any cracked boom, defective welds, or
Sheave and cable roller repair is covered in paragraph 9-
defective structural members must be repaired by
10. Additional repair of the boom attachment is welding
welding or replaced.
of damaged boom structural members. The boom welds
Warning: Boom repairs or alterations of
must be inspected