TM 9-4120-388-14
5-5. EVAPORTOR AND CONDENSER FAN MOTOR (B2) REPAIR - Continued.
(i) Secure thermostat with two screws and spacers.
(j) Secure terminal box with four screws.
(4) To replace bearings (Welco):
(a) Match-mark motor frame and bracket (end bell) to ease reassembly.
(b) Remove eight screws from bracket (end bell)
(c) Remove four screws from bearing retainer.
(d) Carefully separate bracket (end bell) from motor frame.
(e) Carefully pull rotor with shaft and bearing from the frame with stator.
( f Note the position and number of load spring, bearing spacer washer(s), bearings, and bearing retainer
as they are removed.
(g) Check spacer washers and Ioad spring for excessive wear, nicks, or breakage. Replace them if they are
damaged.
Bearings are permanently lubricated and sealed at the time of manufacture. Do
not attempt to clean or relubricate them. Keep bearings in plastic bags or wrap se-
curely in grease-proof paper until needed for assembly.
(h) Remove bearings.
(i)
Examine rotor, stator, and shafts for nicks, gouges, deformations, and evidence of overheating.
Dress high metal defects in shafts with a fine file or stone. If shaft is beyond repair, replace rotor and shaft.
j)
(k) Check bearing retainer for visible damage. Replace it if screw threads are stripped or it is broken or cracked.
Examine motor frame with stator for broken flange, stripped threads, visible damage, shorted windings
(l)
(para 4-63), and evidence of
overheating. If
motor frame with stator is
beyond repair, replace motor.
(m) Coat shaft surfaces with oil (MIL-L-2104, Grade 20) or equal.
(n) Install new bearing on shafts. Be sure that bearing retainer is in place on shaft prior to installing (rear)
bearing.
(o) Coat the bearing cavity of bracket (end bell) with oil (MIL-L-2104, Grade 20) or equal and insert
spacer washers, bearing loading springs, and bearings in same location as removed instep(f) above.
(p) Insert rotor and shaft, with bearing retainer, bearing (rear), and bearing spacer washer(s), in place into
frame with stator.
(q) Carefully work bracket (end bell) onto shaft end keeping the match-marks made at time of disassembly in
alignment.
(r) Align bearing retainer threaded holes.
(s) Secure bearing retainer with four screws.
(t) Secure bracket (end bell) with eight screws. Before final tightening, check for freedom of rotation by
turning shaft by hand. There should be no drag or binding. Correct as necessary and tighten screws.
Check again for binding and drag.
(u) Check end-play of shaft. End-play should be 0.002-0.005 inch (0.51-1 .27 mm). If end-play is not
within limits, disassemble motor and add or remove bearing spacer washers to adjust. Check again
for binding or drag.
5-11