TM 55-203
b. Cleaning, Inspection, and Maintenance
c.
Reassembly
(1) Thoroughly clean all parts in solvent to
(1) Apply a light coat of brake cylinder lubricant
remove oil, grease, and dirt.
to the hollow rod and place the piston and hollow rod in
(2) Renew all worn or damaged parts.
a holding fixture. Then apply the compression spring (9)
(3) Clean the piston lubricator swab and
and nonpressure head (12) Use the locking mechanism
retainer as follows:
of the fixture to hold the compression spring partly
(a) Submerge the assembly in a tank of
compressed.
solvent for a few minutes. Then loosen the lubricator
(2) Place the hollow rod lubricator swab over
swab in its groove with a thin round-edge blade. Return
the hollow rod and push into the recess in the
to solvent tank to dissolve the grease from the swab.
nonpressure head. Put the swab compression ring -on
Brush the outer surface of the swab with a handbrush to
the inner portion of the assembly tool; then slide the tool
aid in removing the old grease. After the swab is
over the outer end of the hollow rod until it contacts the
thoroughly clean, dry with low pressure air.
lubricator swab. With the tool held in this position, push
(b) Renew the lubricator swab when it is
firmly on the outer portion forcing the swab compression
worn, damaged, or in such condition that it cannot be
ring off the tool into position around the lubricator swab.
loosened and raised in its groove to make full contact
Insert brake cylinder lubricant in the nonpressure head
with the cylinder.
recess until the space is about 1/3 full. Place the swab
(c) Submerge the cleaned piston lubricator
retainer over the lubricator swab; then assemble the
in a tank of new journal box oil for at least 10 minutes.
seal rings with their openings staggered. Completely fill
Then allow the assembly to drain for about 10 minutes.
the recess with brake cylinder lubricant and apply the
This saturates the swab and prevents absorption of oil
seal ring retaining plate. Fasten it with capscrews
from the brake cylinder lubricant.
secured with lockwashers.
c. Reassembly of Engine Portion
(3) Apply the piston, lubricator (7) to piston with
flat (felt) side next to piston. Apply the packing cup (4)
(1) Lubricate the cylinder wall and piston
to piston by starting the cup over the edge of piston;
packing cup (21) with brake cylinder lubricant.
while holding it in this position, work the cup into place
(2) Place the piston spring (26) in the pocket of
with the hands. If the cup does not seat properly
the casing (27). Place the piston (22) on top of the
because of trapped air, the air can be removed by
spring and apply the cylinder to the piston over the
raising one side of the cup and pushing the cup into
packing cup.
place with the hands.
(3) Apply pressure to force the cylinder into
(4) Apply shipping cap over the assembled
place against the resistance of the piston spring. Before
piston and secure with bolts to nonpressure head.
pressure is applied and during application of pressure,
hold the knockout lug away from contact with pawl stop
(25) to prevent rupture of this part. The knockout lug is
8-19. Shop Maintenance of Engine Portion of
part of pawl (14) which is accessible through the
Automatic Slack Adjuster
adjuster body opening in casing (27). The pawl can be
reached by removing pipe plug (15).
a. Disassembly of Engine Portion
(4) Stand the ratchet assembly on the brass nut
(1) Remove snap ring (31) (fig 8-29) at end of
end and reassemble the pawl ring, pawls, pins, and
the ratchet nut bearing. Then remove the ratchet
springs on the ratchet nut. Lubricate these parts and the
assembly from the adjuster body end of the casing (27).
ratchet nut bearing with 6 ounces of graphite grease.
(2) Remove check pawl ring (34), pawls (28),
(5) Lower the casing (complete with piston and
pins (29), and springs (30).
spring) in position over the ratchet nut.
(3) Remove ratchet nut felt (11) at the end of
ratchet nut bushing (33).
Saturate the ratchet nut felt (11) with journal oil and put
(4) Remove piston packing cup (21) by using a
in place next to the ratchet nut bushing (33). If the felt is
wooden tool with rounded edges about 1 inch wide and
so worn that it does not seal against the ratchet nut,
3/32-inch thick, to prevent damage to packing cup and
renew the felt.
piston lubricator swab (18) and retainer (20).
(6) Replace felt retainer (32) and snapring (31).
(5) Remove the lubricator swab (18) and
(7) Protect reconditioned engine portions against
retainer (20).
damage and entrance of dust and dirt during storage.
8-34
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