140
Evaporator Fan Coupling Assembly
If the coupling has been removed for other blower assembly com-
ponent repair or replacement, it is critical that the coupling be reas-
sembled and aligned correctly to prevent premature failures.
REASSEMBLING THE COUPLING INTO THE UNIT
(FIG. 46)
1. Prior to reassembling the coupling, loosen the 4 bearing
mounting bolts, which secure the 2 bearings on either side of
the coupling. Remove the drive belts.
2. Reassemble the coupling with the bearings loose. This allows
the coupling to find its own self-alignment position.
3. Check the hub-to-shaft fit for close fitting clearances. Re-
place hubs if high clearances are determined.
4. Check the key for close-fitted clearances on the sides and
0.015 in. clearance over the top of the key. Replace key if
necessary.
5. Be sure that hub flanges, flex members, spacer, and hard-
ware are clean and free of oil.
6. Place the flanges onto the shafts with the hub facing out-
ward. Do not tighten the set screws at this time.
7. Outside of the unit, assemble the flex members to the cen-
ter drive shaft with 4 bolts and nuts. The flex members
have collars that need to be inserted into the smaller hole of
the drive shaft flange.
8. Assemble the flex member/drive shaft assembly to one of the
shaft flanges, using 2 bolts and nuts. Slide the other shaft
flange towards the assembly and assemble using 2 bolts and
nuts. If the shafts are not misaligned, the collar in the flex
member should line up with the shaft flange holes.
9. Torque nuts properly to 95 to 100 ft-lb. Do not turn a cou-
pling bolt. Always turn the nut. Always use thread lubricant
or anti-seize compound to prevent thread galling.
10. The ends of the shafts should be flush with the inside of the
shaft flange. Torque the set screws to 25 ft-lb.
11. After assembly is complete, slowly rotate the shafts by hand
for 30 to 60 seconds.
12. Tighten the bearing mounting bolts, using care not to place
any loads on the shaft which would cause flexure to the
shafts.
13. Reinstall drive belts. (Refer to Belt Tension Adjustment sec-
tion below.)
14. Visually inspect the assembly. If the shafts are overly mis-
aligned, the drive shaft flange will not be parallel with the
shaft flanges.
15. Recheck nut torque after 1 to 2 hours of operation. Bolts tend
to relax after being initially torqued.
Fig. 46 — Evaporator Fan Coupling
CENTER DRIVE
SHAFT
FLEX
MEMBER
SHAFT
FLANGE
BEARINGSSHAFT
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