7-3.
Drifter Drill Repair
a. Disassembly.
(1)
Remove drifter drill (see TM 5-3820-241-12).
WARNING
Dry cleaning solvent P-D-680 is toxic and flam-
mable. Wear protective gloves and use in a well
ventilated area. Avoid contact with shin, eyes, and
clothes and do not breathe vapors. Do not use
near open flame or excessive heat. The flash
point is 100-138 degrees F (38-50 degrees C). If
you become dizzy while using cleaning solvent,
get fresh air immediately and get medical aid. If
contact with eyes is made, wash your eyes with
water and get medical aid immediately.
NOTE
Clean exterior of drifter drill before disassembly.
Use a babbitt hammer to drive off the heavier ex-
terior parts.
Handle parts carefully. Hardened parts might
chip or break if dropped on a hard surface. Other
parts may be damaged by improper handling.
Clean disassembled parts in a solvent. Probe
ports to loosen and remove foreign matter.
(2)
Unscrew front cap (1) and remove bushing (2)
and striker bar (3).
(3)
Remove gland plug (4) from backhead (5).
(4)
Remove air tube (6), washer (7), packing (8),
and O-ring (9). Discard packing and O-ring.
(5)
Remove four nuts (10) and side rods (11).
(6)
Lift off backhead (5) evenly and straight, being
careful not to disturb upper distributor (12).
(7) Remove seal (13) and muffler (14). Discard
seal.
(8) Remove and separate upper distributor (12),
piston (15), cylinder (16), lower distributor (17), and lower
muffler seal (18). Discard seal.
(9)
Remove and discard two O-rings (19) from pis-
ton (15).
(10) Remove and discard two upper (20) and two
lower (21) packings from cylinder (16).
(11) If damaged, remove spring pin (22) from upper
distributor (12) and remove spring pin (23) from cylinder
(16).
(12) Turn drifter drill so that front cover (24) faces
up.
(13) Remove front cover (24).
(14) Remove bearing cup (25), retainer (26), and
spring washer (27) from front cover (24).
(15) Remove bearings (28).
(16) Remove spacer cover (29), gear (30), air motor
assembly (31), and roller bearings (32). If air motor assem-
bly is stuck, lay the drifter drill on its side and gently tap
out the air motor assembly with striker bar (3).
(17) Remove grease fitting (33) from spacer cover
(29).
(18) Remove bearing cone (34) from carrier (35).
(19) Remove two dowel pins (36), then remove car-
rier (35).
(20) Press two shafts (37) out of flange (38). Sepa-
rate upper plate (39), flange (38), motor housing (40), two
bearings (41) and spacer (42), air motor gear (43), lower
plate (44), and two gears (45).
(21) Remove bearing cone (46) from carrier (35).
(22) Remove three gears (47) from shafts (48).
(23) Remove nut (49) from each shaft (48) and press
shafts out of carrier (35).
(24) Remove bearing cup (50) from main housing
(51).
(25) Remove four screws (52) and lo&washers (53)
securing manifold (54) to main housing (51). Remove
manifold and gasket (55). Discard gasket and lockwashers.
(26) Remove four screws (56) and lo&washers (57)
securing cover (58) to main housing (51). Remove cover
and gasket (59). Discard gasket and lo&washers.
(27) Remove grease fitting (60) from main housing
(51).
b. Inspection and Repair.
(1)
Inspect all bushings, bearings, cups, and cones
in accordance with TM 9-214.
(2)
If replacement is required, press two bearings
(61) and bushing (62) out of each gear (45) and replace.
(3)
If replacement is required, press bushing (63)
out of each gear (47) and replace.
(4)
Check striking face of piston (15). If wear is
greater than 0.030 in., grind striking face square. If wear
is greater than 0.050 in., replace piston.
(5)
Check clearance between piston head and cyl-
inder (16). If total clearance is greater than 0.015 in., re-
place piston, cylinder, or both.
(6)
Check clearance between piston stems and up-
per and lower distributors (12 and 17). If total clearance
is greater than 0.006 in., replace piston, distributors, or all
three parts.
(7)
Check for gaulding and burning in the upper
and lower distributors (12 and 17) and the cylinder (16).
Hone to clean or replace.
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