TM 55-1930-209-14&P-21
(f) Place bearing retainers on top of bearing and endplate; then, install retainer bolts and lockwashers.
Tighten bolts to 7-9 Ib-ft torque.
(6) Make a preliminary check of rotor-to-end plate and rotor-to-housing clearances at this time with a feeler
gage. Refer to figure 6-10 for minimum blower clearances.
(7) Install blower rotor timing gears on a standard blower or a smaller diameter rotor blower as follows: one
serration is omitted on drive end of each blower rotor shaft and a corresponding serration is omitted in each gear.
Assemble gears on rotor shafts with serrations in alignment.
(a) Place blower housing and rotor assembly on bench with air inlet side of housing facing up and rear
end (serrated end of rotor shafts) of the blower facing outside of bench.
(b) Rotate rotors to bring omitted serrations on shafts in alignment and facing top of blower housing.
(c) Install same number and thickness of shims on rotor shafts that were removed at time of
disassembly.
(d) Lubricate serrations of rotor shafts with engine oil.
(e) Place teeth of rotor gears in mesh so that omitted serrations inside gears are in alignment and
facing same direction as serrations on shafts.
NOTE
A center punch mark placed in end of each rotor shaft at omitted serrations will assist in aligning
gears on the shafts.
(f) Start both rotor gears straight on rotor shafts with right-hand helix gear on right-hand helix rotor and
left-hand helix gear on left-hand helix rotor, and omitted serrations in gears in line with omitted serrations on rotor shafts.
(g) Thread an installer screw in end of each rotor shaft until it bottoms. Place gear installer over
installer screw and against right-hand helix gear, and gear installer over installer screw and against left-hand helix gear;
then, thread a nut on each installer screw.
(h) Place a clean shop towel between rotors, and another one between rotor and housing to prevent
rotors from turning. Then, turn nuts on installer screws clockwise and force gears into position tight against shims and
bearing inner races.
NOTE
Both gears must be pressed on rotor shafts at same time.
6-24
