
FL2 S
erieS
P
umP
17
Tighten the first rotor nut with a
socket wrench (and Flat Cover Rotor
Bolt Tool on models 15-75). to the rec-
ommended torque (
Table A2, page 5
).
f) To tighten the second rotor place
the dowel on the opposite side of the
pump and tighten the second rotor
nut to the proper torque.
Use feeler gauges to verify the back and
radial clearances between the rotors and
the housing. A depth gauge should be
used to verify the front clearance (see
Table A3
).
b
ack
F
ace
c
Learance
The rotor to housing back face clearance
is maintained by the gapping spacer.
To check the back clearance, mount the pump housing onto the gearbox. Make sure to use
washers and dome nuts on the long housings studs, to secure the housing. Assemble the gap-
ping spacer, rotor and rotor nut onto the shaft. (Refer to
Table A2
for the proper rotor nut
torque.) Measure the clearance between the back face of the pump housing and the back of the
rotor with a feeler gauge. Check the reading with the recommended clearance,
Table A3
.
t
oo
m
uch
c
Learance
If the clearance is greater than the clearance specified in
Table A3
, remove the gapping spacer
or the rotor and gapping spacer on the FL2 15. Machine and lap the o-ring end of the gapping
spacer to the required length. Lap the gapping spacer until the shim faces are perfectly flat and
the spacer thickness is the same around the entire circumference of the shim. (Recommended
lap compound – Liquid Diamond 14 microns)
Re-assemble the gapping spacer, rotor, and rotor nut. Recheck the back face clearance.
Assemble the pump wet end up as outlined in the “Pump End Assembly” section.
n
ot
e
nough
c
Learance
If the back clearance is less than the clearance specified in
Table A3
a thicker shim must be
added. Remove the gapping spacer. Install a new standard length gapping spacer. Follow the
procedures outlined in the
Too Much Clearance
section above.
p
ump
e
nD
a
SSembLy
(
cont
.)
g) Install the cover o-ring into the o-ring groove in the cover. Install the cover and tighten the
dome nuts.
h) Rotate the drive shaft to verify that the pump turns freely.
Do not rotate the shafts with the
cover removed. Rotors and housing could be damaged.
i) Check that the oil level is in the center of the oil level sight glass.
j) Install all required shaft guards. Install inlet and outlet piping. Verify that all valves on the
suction and discharge side of the pump are open. Follow proper lockout procedures to re-
supply the pump drive with the power. Start the pump.
Figure 18