Brandt GRAIN VAC 5000, Operator And Parts Manual

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5.15.2 Replacing the Fan Rotor
1. Remove the front big belt shield.
2. Loosen off the fan drive belt by loosening the nut on the belt idler adjustment bolt and remove the fan
drive belt off of the small pulley.
3. Remove the twenty four 3/8” nuts that hold the fan housing front plate to the fan housing, an 9/16” air
impact wrench works well here.
4. Remove the fan housing front plate assembly from the fan housing. The silicone that is used to seal the
housing will be difficult to pry loose.
5. Remove the Fan Rotor from the shaft using the bolts used to hold the tapered bushing in the fan hub.
Loosen the setscrew in the tapered bushing and remove the bushing from the shaft.
6. Before beginning reassembly, check the tapered bushing in the new fan rotor. The keyway in the
tapered bushing must line up with the small letter ‘K’ that has been stamped in the cast hub bolted to
the rotor. See Fig. 39. If the keyway is not inline with the ‘K’, the rotor will out of balance and cause
premature failure of the bearing box.
7. Install the Fan Rotor onto the Bearing Box shaft. Push the tapered bushing on until it is flush with the
end of the shaft. Tighten the setscrew in the bushing onto the shaft and begin tightening the tapered
bushing bolts. Tighten the bolts evenly by slowly tightening the bolts in a circular pattern. On the final
round, torque the bolts to 22 ft.lbs.
8. Check the position of the Fan Rotor relative to the Fan Front Plate. The rotor must positioned
4 15/32” from the Fan Front Plate as shown in Fig. 39. If required, loosen the six Bearing Box
mounting bolts and using the three adjustment bolts on the Bearing Box, adjust the position of the Fan
Rotor until it is 4 15/32” from the Fan Front Plate. Make sure the rotor is evenly spaced around the
entire circumference. Tighten the six Bearing Box mounting bolts.
9. Install the fan housing front plate assembly back onto the 24 bolts on the fan housing. Reseal the fitting
with silicone and tighten the 24 nuts.
10. Check the gap between the fan rotor and the inlet tube as shown in Fig. 38. Make sure the gap
between the fan rotor and the inlet tube is even all around. Read the instructions in the “If the Fan is
Rubbing” section and make any adjustments.
11. Reinstall the belt. See the “Belt Tensioning” section 5.1.