Great Plains 3P-FF900 Operator Manual - Manual (Page 37)

12/8/2009 500-643M
35 Maintenance and Lubrication
Pump Maintenance and Repair
Scott and Ace Pumps
The centrifugal pump is designed for long life and ser-
vice. Through the years, there may be a need to replace
the mechanical seal or service some component of the
pump. A mechanical seal may weep slightly, but if it starts
to drip, the pump will have to be disassembled. Before
disassembling the pump, be sure to wash it out with fresh
water.
If the pump is leaking, before removing it from the spray-
er, run the pump with adequate water in the tank to
diagnose the actual pump problem.
Ace Hydraulic Pump Seal Replacement
Refer to Figure 14
Disassembly
1.
Remove four 5/16” hex head cap screws (19) from
rear of motor (18). Remove motor (18) and coupler.
2. Remove rear internal bearing snap ring (11).
3. Remove four 3/8” x 3/4” hex head cap screws (9)
from mounting frame (8). Remove volute (2).
4. Remove 3/8” lock nut (3) from shaft (16). Insert flat
file into impeller vane to hold stationary. CAUTION:
Excess torque may damage plastic impellers.
5. Press shaft (16) out of impeller using one 5/16” hex
head cap screw from step 1. Remove impeller (5),
key (15), and rotating seal member (6).
6. Press shaft/bearing assembly out of frame.
7. Remove stationary seal member (7) by prying out
with screwdriver or pressing out from motor end of
pump housing.
8. Remove o-ring (20) from shaft groove.
NOTE: If replacing only pump seal: 1) Press shaft/
bearing assembly into frame. 2) Reinstall rear internal
bearing snap ring. 3) Skip to Assembly step 8.
9. Press bearings off of shaft.
10. Remove forward internal bearing snap ring (11).
Assembly
1.
Install forward internal bearing snap ring (11) in
mounting frame (8).
2. Press in forward bearing (12) from rear side of mount-
ing frame (8) to snap ring (11).
3. Install two external shaft retainer rings (13) with spac-
er (14) between on shaft (16).
4. Press shaft assembly through forward bearing (12)
until forward shaft snap ring (13) rests against inner
face of forward bearing (12).
5. Press rear bearing (12) over shaft (16).
6. Insert rear internal bearing snap ring (11).
7. Slide rubber slinger (10) over shaft (16) and push back
to front bearing (12).
8. Clean old sealant from mounting frame seal bore.
9. Install o-ring (20) in shaft groove.
10. Apply non-hardening Type 2 Permatex or similar un-
der stationary seal flange.
11. Place stationary portion of seal (17) over shaft and
press into seal bore cavity. Use 1-3/8” ID pipe or PTO
adapter to press seal flange evenly on all sides.
12. Install rotating portion of seal (6) over shaft (16) and o-
ring (20) by hand. The two polished
seal faces should face each other.
Avoid contacting polished seal faces.
13. Insert key (15) in keyway (5) and in-
stall impeller (5) on shaft (16).
14. Place lock washer (4) and 3/8” lock
nut (3) on shaft (16). Tighten nut (3).
15. Replace volute o-ring or gasket (7),
volute (2), and four 3/8” x 3/4” cap
screws (9).
16. Position coupler in pump shaft slot
and fill cavity surrounding coupler
with grease.
17. Install motor (18) by aligning motor
tang and coupler slot. Rotate motor
(18) until nameplate faces up.
18. Install four 5/16” cap screws (19).
Figure 14
Ace Hydraulic Pump
23373