Inspect blower rotor lobes for smoothness. Inspect
rotor shaft serrations and bearing surfaces for wear or
Check the finished faces of the end plates to see that
they are smooth and flat.
Check the finished ends of the blower housing,
which receive the end plates, to see that they are flat and
free from burrs. The end plates must set flat against the
Check blower timing gears for wear or damage.
If either timing gear is worn or damaged sufficiently
to require replacement both gears must be replaced
as a set
Inspect the inside of the housing to see that the
surfaces are smooth. The blower drive shaft should be
straight and true. Shaft serrations should be clean and
straight. You should replace all worn or excessively
damaged blower parts.
After you have cleaned and inspected all the blower
parts, reassemble the blower as prescribed in the
manufacturers maintenance and service manuals.
A diesel engine may be equipped with a
supercharger (fig. 5-37). The supercharger is a
gear-driven air pump that uses rotors to force air into the
engine cylinders when a requirement for more power
exists. The supercharger must be maintained
Remove the outlet connection of the suprcharger
and visually check the ends of the rotors and case for
evidence of oil leaking from the supercharger seals.
Rotors will always show some oil from the vapor tube,
which is connected to a rocker housing cover. However,
only the appearance of wet oil at tie ends of the rotors
would be cause for changing the seals of the
supercharger. Be sure to check the lubricating oil lines
and connections for any leaks. Correct these conditions
When the supercharger has to be removed from the
engine, follow the procedures given in the
manufacturers service manual.
If you have to disassemble the supercharger, be
careful when you remove the intake and discharge
connections. Be sure to cover both openings. To prevent
damage to its finished surfaces, usually made from
aluminum, wash the outside of the supercharger with
mineral spirits. Use the correct service tools and follow
recommended disassembly procedures in the
manufacturers maintenance and repair manuals.
Cleaning and Inspecting
As the supercharger parts are disassembled, you
should clean and dry them thoroughly with filtered
compressed air. Discard all used gaskets, oil seals,
recessed washers, roller bearings, and ball bearings.
Replace these parts with new ones.
Inspect the rotors, housing, and end plates for
cracks, abrasions, wear spots, and buildup of foreign
material. With a fine emery cloth, smooth all worn spots
found. Discard cracked, broken, or damaged parts.
Remember, rotors and shafts we not separable. They
must be replaced as a matched set or unit.
Inspect the drive coupling for worn pins, distorted
or displaced rubber bushings, and damaged or worn
internal splines. Examine the hub surface under the oil
seal and replace the coupling if its surface is grooved or
Check the gear fit on the rotor shafts and the gear
teeth for evidence of chatter and wear. Replace the rotors
and gears if they are not within the required tolerances.
Inspect all dowels, oil plungers, piston ring seals,
and gasket surfaces. Replace them as necessary.