TM 5-3810-294-34
Section III. GENERAL MAINTENANCE
purposes, the entire bearing should be immersed in an
2-5.
General Disassembly Instructions
oil bath, or heated in an oven, for sufficient time to
The following points should be kept in mind during the
ensure that it is heated throughout.
disassembly of any component.
d. Never force a bearing on a shaft if the fit
a. Disassembly should be limited to that
appears to be so tight that the inner race will be
required for specific repairs. Never disassemble an
distorted. Either polish the shaft seat or heat the
assembly beyond the point necessary to fix the trouble.
bearing, or do both.
b. Never use heat from a torch to assist in
e. Inspect all grease passages to be sure they
removing parts unless the parts to be heated are already
are open and clean.
damaged beyond repair. Excessive heat will damage the
f. Smooth out all nicks, burrs, or galled spots on
parts beyond repair.
shafts, bores, pins or bushings.
c. Never use more force than necessary while
g. Check the fit of keys in keyways. File or
dismantling an assembly. In most cases, a great deal of
grind the key, if necessary, to make sure it fits without
force is not required.
2-6.
General Inspection Instructions
h. Roller bearing spacers must be reassembled
When any major component has been removed and
in the bearing from which they were removed. They are
disassembled, all parts should be inspected for wear or
ground to fit individual bearings.
damage. Particular attention should be paid to the
2-8.
Brake Band Repair
following items.
a. Clean all parts thoroughly, using kerosene,
The only repair possible for brake bands is lining
replacement. Linings are all of the riveted type, and all
diesel oil, or a suitable commercial solvent. Never use a
are repaired by drilling out the rivets, installing a new
b.
hot alkaline solution on finished parts or bearings.
lining, and riveting it in place. All linings must be
Inspect all gears for worn, cracked, or broken teeth.
replaced when they reach a point where the lining
c. Inspect all bushings for wear, scoring, or
covers the rivet, at the point of most lining wear, by 1/16
galling.
inch or less.
d. Replace all oil seals and O -rings.
2-9
Welding Procedure for "T-1" Steel
e. Replace all gaskets, making sure the
a. General. The upper turret flange is the only
replacement gaskets are of the same thickness as the
place in this machine where high strength "T-l" steel is
old gasket. Use gasket material of the same
used. The following instructions cover the methods to
be used in welding this high strength alloy steel.
b. Electrode Selection. The single most
play, distorted races, and roller wear or damage.
important thing to remember in the welding of high
strength steels is to use the right electrode. Be sure to
bearing grease before reassembly.
g. Smooth out ridges on shafts caused by wear.
use only electrodes with "low-hydrogen" coatings for
manual arc welding. An alternative method would be to
Be particularly careful to inspect all surfaces on which
use a welding method, such as inert gas shielded arc, or
seal lips seat. These surfaces must be very smooth to
submerged arc, which is inherently "low-hydrogen."
prevent wearing away the seal lips, which will cause oil
Hydrogen is the main cause of failure in welding high
or grease leaks.
strength alloy steel. Hydrogen which remains in the
h. Inspect all threaded items and replace those
weld will cause cracking when the welded steel cools.
with damaged threads.
This cracking is not visible at the surface of the weld, but
i. Inspect all other parts for any evidence of
will occur beneath the visible surface. In order to insure
damage. Replace or repair any part which is in
the use of low-hydrogen rods, use rods with classification
questionable condition. The cost of the part is often
numbers ending in 15, 16, 18, or 28. No other rods are
minor in comparison with the cost of redoing the job if
acceptable. Samples of acceptable rods are E7028,
the part should fail.
E8015, E9016, and E11018. Note that all of these
2-7.
General Reassembly Instructions
numbers end in one of the four sets of 2 digits
The following points should be kept in mind when
previously mentioned. When welding "T-1" steel to a
reassembling any component of this machine.
lower strength steel, the electrode strength should be
a. When torque values are specified, be sure to
the same as recommended for the lower strength steel,
use a torque wrench and tighten as directed.
but must remain of the low-hydrogen type. Also, when
dog
suitable bearing grease before final assembly.
c. If a bearing is to be heated for assembly
2-7
