Replace all worn or excessively damaged blower parts.
Several precautions are given below to assure proper
assembly of the rotors and gears for correct blower
The lobes on the upper blower rotor and the teeth on its
gear form a right-hand helix while the lobes and teeth of
the lower rotor and gear form a left-hand helix.
Therefore, a rotor with right-hand helix lobes must be
used with a gear having right-hand helix teeth and vice
One serration is omitted on the drive end of each blower
rotor shaft and a corresponding serration is omitted in
each gear. Assemble the gears on the rotor shafts with
the serrations in alignment.
Fig. 9 - Blower End Plate and Lip Type Oil Seal
With this precaution in mind, proceed with blower
c. Place the short end of oil seal remover and
assembly, referring to Figs. 7 through 15 as directed in
installer J 6270-3 in the oil seal and press the oil
seal into the end plate until the shoulder on the
1. Install the lip type oil seals as follows (Fig. 9).
A step under the shoulder of the
a. Support the blower end plate, finished surface
installer will position the oil seal
facing up, on wood blocks on the bed of an
approximately .005" below the
finished face of the end plate. This
is within the .002" to .008" specified.
If oversize oil seals are being used in
the blower end plates, use installer J
d. Install the remaining oil seals in the end plates
6270-28 to install the oversize oil seal
in the same manner.
spacers on the rotor shafts.
Assemble Rotors and End Plates
b. Start the oil seal straight into the bore in the end
No gaskets are used between the end plates and the
plate with the sealing edge facing down (toward
housing; therefore, the mating surfaces must be
the bearing bore).
perfectly flat and smooth.
Apply a rubber base sealant as required to avoid
leakage between the end plates and the blower housing.
Be sure no sealant protrudes into the
blower housing. Also, the sealant
must not prevent the end plates from
laying against the housing.
1. Install the blower front end plate. Make sure the
mark TOP on the outer ribbed side is at the top of the
blower housing, identified by the flange which supports
the housing on the top edge of the cylinder block (Fig.
Fig. 8 - Installing Oil Seal in Blower End Plate using
Tool J 6270-3.
The front and rear end plates of the blower are