| Tweet |
Custom Search
|
|
|
||
 TM 55-1905-219-14-4
3-12. BLOWER - MAINTENANCE INSTRUCTIONS (Cont).
LOCATION
ITEM
ACTION
REMARKS
Inspection
The blower may be inspected for any of the following conditions without being removed from the engine.
However, the air silencer and adaptor, or the air inlet housing, air shutdown housing and adaptor must first be
removed.
When inspecting a blower on an engine with the
engine running, keep fingers and clothing away from
moving parts and run the engine at low speeds only.
a. Dirt or chips, drawn thru the blower, will make deep scratches in the rotors and housing, and throw up
burrs around such abrasions. If burrs cause interference between the rotors and the housing, replace the
blower(s).
b. Leaky oil seals are usually manifest by the presence of oil on the blowerrotors or inside surfaces of the
housing. This condition may be checked by running the engine at low speed and directing a light into the rotor
compartment at the end plates and the oil seals. A thin film of oil radiating away from the seals toward the inlet
of the blower is indicative of leaking seals.
c. A worn blower drive, resulting in a rattling noise inside the blower, may be detected by grasping the
right-hand helix rotor firmly and attempting to rotate it. The rotors may move from 0.3750 inch (0.9525 cm) to
0.625 inch (1.588 cm), measured at the lobe crown, with a springing action. When released, the rotors should
move back at least 0.250 inch (0.635 cm). If the rotors cannot be moved as directed above, or if the rotors
move too freely, the flexible blower drive coupling should be inspected and replaced if necessary. The drive
coupling is attached to the right-hand helix blower timing gear.
d. Loose rotor shafts or damaged bearings will cause rubbing and scoring between the crowns of the roto
r
lobes and the mating rotor roots, between the rotors and the end plates, or between the rotors and the housing.
Generally, a combination of these conditions exists. Worn or damaged bearings will cause rubbing between
mating rotor lobes at some point or perhaps allow the rotor assemblies to rub the blower housing or the end
plates. This condition will usually show up at the end where the bearings have failed. Replace the blower(s).
3-479
|
||
|
||
