a. Clean all metal parts in dry cleaning solvent
(1) Remove nut (58), washer (57), and boot
(Federal Specification P-S-661) and dry
thoroughly with compressed air. Oil all internal
(2) Rotate worm shaft (33) until index mark
parts with engine oil (OE) and place on clean cloth
on sector shaft (74) is perpendicular to the center
or paper. Wrap bearings and fine machined parts in
line of the gear.
waxed paper or cheese cloth to protect surfaces.
(3) Remove screws (60) and washers (59).
b. Do not wipe any valve parts with cloth. Lint
Tap end of sector shaft (74) with a soft hammer to
left from cloth may cause binding and sticking of
loosen and remove side cover (63), with sector gear
the closely fitted parts.
attached, from housing. Remove seal (47).
16-5. Inspection and Repair
(4) Remove screws (55) and remove seal
(5) Remove nut (61). Turn adjusting screw
b. If either worm shaft or ball nut are damaged
(73) clockwise to disengage sector shaft (74) from
replace both parts as a complete assembly.
cover (63). Remove screw (73) and retainer (72(.
c. Replace rack piston and/or sector shaft if
(6) Remove plug (62) from cover. Remove
teeth are damaged or worn. Replace piston if
retaining ring (71) and remove seal (170) and
machined surfaces are damaged.
washers (66 and 65) from cover. Pull bearing (64)
d. Check all bearings and bearing surfaces in
from cover with a suitable puller.
housing and cover for wear or damage. Replace
(7) Remove screws (26) and washers (27)
worn or damaged parts.
from adapter (28). Rotate upper cover (8) sixty
e. Inspect valves for wear and damage to sealing
degrees and lift cover slightly. Then remove cover,
surfaces and ports. Replace valves if worn or
valve (19), adapter (28), and balance of assembly
from housing (48). Remove seal (46). Remove nut
f. Replace thrust washers and roller bearings
(69), adjusting screw (68) and O-ring (67).
if worn or damaged.
(8) Remove setscrew (42) from piston (45).
g. Replace all seals, O-rings, and gaskets.
Rotate piston rack so that teeth are in a down
position. Disengage rack from worm shaft (33) and
16-6. Reassembly and Installation
ball nut (34) slowly, to expose approximately 1
inch of ball nut. Clean surface of ball nut and wrap
tape around ball nut to prevent loss of steel balls.
Remove piston rack from worm shaft.
assemble the gear assembly as follows:
(9) Remove piston ring (41), valve seat (43),
(1) Place housing (48) on a wooden block to
and valve (44) from piston rack.
protect the side cover machined surface and
(10) Cut worm seal (36) and remove seal.
carefully press bearing (491 into the housing.
Remove retaining ring (40) and remove washer
Bearing should extend 3/16 inch from housing
(39), washer (38), cup (37), and backup washer
after installation. Check bearing for free movement
(35) from worm shaft. Place 0.803 diameter
mandrel on bottom end of worm shaft and carefully
(2) Coat 0 -ring (67) with grease (GAA) and
unscrew ball nut onto mandrel.
install in the groove of adjusting screw (68). Install
(11) Remove seal (1) and retaining ring (2).
the adjusting screw in the bore of the housing and
Remove screws (6) and remove upper cover (8),
screw in until 7/8 inch of thread is exposed.
with nut (7), screw (9) and O-ring (10). Remove
Install nut (69) on adjusting screw.
(3) Clamp worm shaft (33) in a soft jawed vise
with the splined end extending horizontally from
(12) Bend tabs of washer (12) to release nut
the vise. Install thrust washer (25), spacer (24),
(11), and remove the nut from the worm shaft.
roller bearing (23) and thrust washer (22) in valve
Remove key washer (131, thrust washers (14 and
17), bearing (16) and spacer (15) from the shaft
Note. Item (19) is a subassembly.
Remove valve (19) from the shaft. Remove seals
(20 and 21).
(13) Remove thrust washers (22 and 25),
(4) Install the valve assembly on worm shaft
bearing (23), spacer (24), and seal (29) from(
(33). Extreme care should be used when installing
adapter (28). Remove worm shaft (33) from the
the valve assembly so that the reaction plungers in
adapter. Remove retaining ring (321, seal (31) and
the valve assembly do not fall out. Install thrust
washer (30) from the adapter.
washer (17), spacer (15), roller bearing (16), thrust
(14) Remove seal assembly (51), backup
bearing (14), key washer (13), tang washer (12)
washer (52), and seal (51) from seal adapter (54).
and nut (11).
(15) Remove retaining ring (50) and roller.
(5) Carefully tighten nut (11) until there is
bearing (49) from housing (48).
zero bearing end play. Back the nut off ap-