and cables) should be parallel to each other and as near
i. Shims. When shims are removed, tie them together
perpendicular as possible to the top of the object being
and identify them as to location. Keep shims clean and
lifted. When it is necessary to remove a component on
flat until they are reinstalled.
an angle, the capacity of an eyebolt diminishes as the
j. Bearings. (1) Anti-friction Bearings. When an anti-
angle between the supporting member and the object
friction bearing is removed, cover to keep out dirt and
becomes less than 900. Eyebolts and brackets should
abrasives. Wash bearings in non-flammable cleaning
never be bent and should only have stress in tension. If a
solution and allow to drain dry. The bearing may be dried
part resists removal, check to be certain all nuts and
with compressed air but DO NOT SPIN THE BEARING.
bolts have been removed and that an adjacent part is not
Discard the bearings if the races and balls or rollers are
interfering.
pitted, scored, or burned. If the bearing is servicable,
c. Disassembly and Reassembly. When assembling an
coat it with oil and wrap it in clean paper. Do not un- wrap
assembly, complete each step in turn. Do not partially
new bearings until time of installation. The life of an anti-
assemble one part and start assembling another part.
friction bearing will be shortened if not properly
Make all adjustments as recommended. Always check
lubricated.
the job after it is completed to see that nothing is
(2) Double row, tapered bearings. Double row, tapered
overlooked.
roller bearings are precision fit during manufacture and
d. Service Tools. Two and three arm puller assemblies
the components are not in- terchangeable. The cups,
can be used to remove gears, bearings, hubs, bearing
cones, and spacers are usually etched with the same
cages, shafts, etc. Bearing pulling attachments can be
serial number and letter designator. If no letter
used with forcing bolts in combinations with arm pullers.
designators are found, wire the components together to
When pressing one part into another, use anti-size
assure
correct
installation.
Reusable
bearing
compound or a molybdenum disulfide-base compound to
components should be reinstalled in their original
lubricate the mating surfaces. Assemble tapered parts
positions.
dry. Before assembling parts with tapered splines, be
(3) Sleeve bearings. DO NOT INSTALL SLEEVE
sure the splines are clean, dry, and free from burrs.
BEARINGS WITH A HAMMER. Use a press if possible
Position the parts together by hand to mesh the splines
and apply the pressure directly in line with the bore. If it is
before applying pressure. If parts which are fitted
necessary to drive on a bearing, use a driver or bar with
together with tapered splines are not tight, inspect the
a smooth flat end. If a sleeve bearing has an oil hole,
tapered splines and discard the parts if worn.
aline it with the oil hole in the mating part. (4) Bearing
e. Bolts and Bolt Torque.A bolt which is too long may
installation. Bearings which require expansion for
"bottom" before the head is tight against the part it is to
installation should be heated in oil not to exceed 2500F.
hold. The threads can be damaged when a "long" bolt is
(1216C). When more than one part is heated to aid in
removed. If a bolt is too short, there may not be enough
assembly, they must be allowed to cool and then
threads engaged to hold the part securely. Apply proper
pressed together again. Parts often separate as they
torque values to all bolts and nuts when assembling
cool and shrink. Lubricate new or used bearings before
equipment. When a specific torque value is required, it is
installation. Bearings that are to be preloaded must have
listed in paragraph 1-5 c.
a film of oil over the entire assembly to obtain accurate
f. Locks. Flat metal locks must be installed properly
preloading. When installing a bearing, spacer, or washer
to be effective. Bend one end of lock around the edge of
against a shoulder on a shaft, be sure the cham fered
the part. Bend the other end against a flat surface of the
side is toward the shoulder. When pressing bearings into
nut or bolt head. Always install new locks in
a retainer or bore, apply pressure to the outer race. If a
compartments which house moving parts. When
bearing is pressed on a shaft, apply pressure to the inner
installing lockwashers on housings made of aluminum,
race.
use a flat washer between the lockwasher and the
(5) Preloading bearings. Preload is an initial force placed
housing.
on the bearings at the time of assembly. Determine
g. Lines and Wires. When removing or disconnecting
preload or end clearance from the tabulated data. Care
a group of lines or wires', tag each one to assure proper
should be exercised in applying preload. Misapplication
reassembly.
of preload to bearings requiring end clearance can result
h. Lubrication. Where applicable, fill the
in bearing failure.
compartments of the component serviced with the
k. Gaskets. Be sure the holes in gaskets correspond with
amount, type, and grade of lubricant recommended in
the lubricant passages in the mating parts. If it is
the lubrication order.
necessary to make gaskets, select stock of the proper
type and thickness. Be
2-3
