101-C00 Page 12/20
PUMP ASSEMBLY
Before reassembling the pump, inspect all component
parts for wear or damage, and replace as required. Wash
out the bearing/seal recess of the head and remove any
burrs or nicks from the rotor and shaft.
1.
Reassemble the OUTBOARD side of the pump first:
For a CLOCKWISE rotation pump, position the pump
cylinder with the INTAKE port to the
left
.
For a COUNTERCLOCKWISE rotation pump, position
the pump cylinder with the INTAKE port to the
right
.
2. Apply a small amount of quality O-ring lubricant in the
head recess. With new O-rings installed, push the
mechanical seal assembly (153) into the recess of the
head with the seal jacket drive tangs inward. The pin in
the seal stationary seat MUST be between the lugs in the
back of the head recess.
3. Apply a small amount of O-ring lubricant to the O-ring
groove on the inside face of the head to facilitate
installation. Install a new head O-ring (72) in the groove
by laying the O-ring flat and starting in on one side of the
groove, stretching ahead with the fingers, as shown in
Figure 8.
Figure 8 – Head O-Ring Installation
4. Install the head (20) on the outboard side of the cylinder.
Install and snug up four head capscrews (21) 90°
apart.
5. Hand pack the ball bearing (24) with grease. Refer to
"Lubrication" in the Pump Maintenance Section for the
recommended grease.
6. Install the bearing into the head recess. The bearing balls
should face outward, with the grease shield inward.
Ensure the bearing is fully and squarely seated against
the mechanical seal.
7. Turn the pump cylinder around and begin assembly on
the opposite, inboard end.
8. Remove the vanes (14) and push rods (77) from the rotor
and shaft assembly. Inspect for wear and damage, and
replace as follows:
a. Partially install the non-driven end of the rotor and
shaft (13) into the open side of the pump cylinder.
b. Leave part of the rotor outside of the cylinder so that
the bottom vanes can be installed and held in place
as the push rods are installed in the push rod holes
of the rotor. Insert the new vanes into the rotor slots
with the rounded edges outward, and the vane relief
grooves facing TOWARDS the direction of rotation.
Refer to Figure 4 in “Vane Replacement.”
c.
After the bottom vanes and push rods are installed,
insert the rotor and shaft fully into the cylinder.
d. Install the remaining vanes into the top positions of
the rotor.
Rotate the shaft by hand to engage the
drive tangs of the mechanical seal jacket in the
rotor slots.
9. Apply a thin coating of quality O-ring lubricant on the
inboard shaft to aid installation. Install the inboard head,
mechanical seal, and bearing as instructed in steps 2
through 6.
10. Rotate the shaft by hand to engage the seal drive tangs,
and to test for binding or tight spots. If the rotor does not
turn freely, lightly tap the rims of the heads with a soft
faced mallet until the correct position is found. Install all of
the remaining head capscrews for each head and
uniformly tighten, then torque to 25 lbs ft (34 Nm).
Figure 9 – Locknut Assembly
11. LOCKNUT ADJUSTMENT –
GNX(H)2,GNX(H)2.5, and GNX(H)3 Models Only
It is important that the bearing locknuts (24A) and
lockwashers (24B) be installed and adjusted properly.
Overtightening locknuts can cause bearing failure or a
broken lockwasher tang. Loose locknuts will allow the
rotor to shift against the discs, causing wear. See Figure
a. On both ends of the pump shaft, install a lockwasher
(24B) with the tangs facing outward, followed by a
locknut (24A) with the tapered end inward. Ensure the
inner tang "A" of the lockwasher is located in the slot
in the shaft threads, bending it slightly, if necessary.
b. Tighten both locknuts to ensure that the bearings are
bottomed in the head recess.
DO NOT overtighten
and bend or shear the lockwasher inner tang.
c. Loosen both locknuts one complete turn.
d. Tighten one locknut until a slight rotor drag is felt
when turning the shaft by hand.
e. Back off the nut the width of one lockwasher tang "B".
Secure the nut by bending the closest aligned
lockwasher tang into the slot in the locknut. The pump
should turn freely when rotated by hand.
f. Tighten the opposite locknut by hand until it is snug
against the bearing. Then, using a spanner wrench,
tighten the nut the width of one lockwasher tang “B”.
Tighten just past the desired tang, then back off the
nut to align the tang with the locknut slot. Secure the
nut by bending the aligned lockwasher tang into the
slot in the locknut. The pump should continue to turn
freely when rotated by hand.
g. To check adjustment, grasp the nut and washer with
fingers and rotate back and forth. If this cannot be
done, one or both locknuts are too tight and should be
alternately loosened one stop at a time 0.001"
(0.025mm). Begin by loosening the locknut adjusted
last.
