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MAINTENANCE
9. DISC – 4-inch pumps
Place the disc (71) against the head (20) with the seal
cavity inward and the disc relief hole located so that when
the head is mounted on the pump with the “Blackmer”
name in an upright position, the disc relief hole will be at
the pump intake, (see Figure 13). Install and tighten the
disc machine screws and lockwashers (71A and 71B).
The drive tangs of the seal jacket should protrude through
the center hole of the disc.
Figure 14 - Disc Relief Hole Location (4” pumps)
10. Install a new head O-ring (72) in the groove on the inside
face of the head (20). Lay the O-ring flat and start in on
one side of the groove, stretching ahead with the fingers,
as shown in Figure 15.
Figure 15 – Head O-ring Installation
11. Carefully install the head assembly (20) on the pump
casing (12). Rotate the head so that the drain hole,
located at the back of the bearing cavity, faces downward
when the pump is mounted for operation. Install and
uniformly tighten four head capscrews (21) 90°
apart;
torque to 30 lbs ft (40.7 Nm).
4-inch pumps: Make sure the head is mounted with the
‘Blackmer’ name upright and the disc relief hole towards
the intake side of the pump. The seal jacket drive tangs
must be engaged in the rotor slots
12. Hand pack the ball bearing (24) with grease. See the
"Lubrication" section for recommended greases.
13. Install the bearing (24) into the head recess. The bearing
balls should face outward, with the grease shield inward.
Ensure the bearing is fully and squarely seated in the
head (20).
14. Turn the pump casing around and remove the outboard
head and disc previously installed.
15. Install the outboard head, O-ring (72), mechanical seal
(153), disc (71) and bearing (24) per steps 7 through 14.
16. Rotate the shaft by hand to engage the mechanical 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 the remaining head capscrews (21) for each head
(20) and uniformly torque to 30 lbs ft (40.7 Nm).
17.
LOCKNUT ADJUSTMENT
It is important that the bearing locknuts (24A) and
lockwashers (24B) be installed and adjusted properly.
Overtightened locknuts can cause bearing failure or a
broken lockwasher tang. Loose locknuts will allow the
rotor to shift against the discs (71), causing wear. See
Figure 16.
Figure 16 - Locknut Adjustment
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 (24A) to ensure that the bearings
(24) 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 (24A) by hand until it is
snug against the bearing (24). Then, using a spanner
wrench, tighten the nut the width of one lockwasher
tang. 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 (.001" – 25
microns). Begin by loosening the locknut adjusted last.
18. Inspect the grease seal (104) for wear or damage and
replace as required. Grease the outside diameter of the
grease seal and push it into the inboard bearing cover
(27) with the lip of the seal inward.
