Great Plains 3P300 Operator Manual - Manual (Page 50)

46 3P300 S/N HH1113+ Great Plains Manufacturing, Inc.
500-103M-A 09/14/2009
Pump Maintenance & Repair
Great Plains PTO Pump
The Great Plains pump is designed for long life and ser-
vice. After some years, a mechanical seal may weep
slightly, but if it starts to drip, the pump needs disassem-
bly. Before disassembling the pump be sure to flush it
with fresh water. The Parts manual has current compo-
nents part numbers.
Refer to Figure 28
Before removing a leaking pump, run the pump with ade-
quate water in the tank to diagnose the actual pump
problem. If fluid leaks out between the front suction
housing
and the rear volute housing , the housing
gasket may be dried out. Give the gasket adequate
time to absorb moisture and swell up. If necessary,
retighten the volute housing
by alternating on opposite
sides until all nuts are torqued to 16 - 18 ft.-lbs. It is a
good practice to apply grease to both sides of the gasket
to prevent shrinkage.
If seal replacement is required:
1. Disassemble pump and clean all components.
2. Assemble the ceramic ring seat of the mechanical
seal
into the volute housing of the pump. Make
sure the ceramic seat is positioned square into the
volute housing.
3. Clean off any grease or dirt from pump shaft and
dry the shaft so the rubber bellows on the mechani-
cal seal will adhere to the shaft properly when
assembled.
4. Bolt up the pump input bearing housing (not shown)
to the volute housing
using bolts , and with
spacers (not furnished) for alignment and assembly
of the shaft seal.
5. Assemble the seal without its spring, on the pump
shaft by pushing on the inside rubber portion of the
seal using water as the lubrication. The graphite seal
face should touch the white ceramic seat face. The
rubber bellows adhering to the pump shaft should
not protrude more than
1 ⁄
16
in (1.6mm) beyond the
stainless steel ring on the impeller side of the seal.
6. Assemble the seal’s spring and the impeller, being
careful not to move the mechanical seal that has
been positioned on the pump shaft. Torque the
impeller bolt
16-18 ft-lbs (22-24 N-m).
7. Remove the three bolts and spacers. Using gun
grease, lubricate the gasket
. Assemble the gasket
and suction housing using bolts, flat washers
and locknuts. Torque nuts 16 - 18 ft./lbs.
Figure 28
GP Centrifugal Pump Assembly
11591
5 8
6
8
9
6
7 8
10
8 2 3 4
7
1
6
6 5