BLACKMER LDF1A, Installation, Operation And Maintenance Instructions

501-

F

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MAINTENANCE 

33.  Using a keyed coupling half, hold the shaft end and 

tighten the locknut with a spanner wrench to pull the 
head against the cylinder. DO NOT overtighten and 
shear the inner tang of the lockwasher. 

34.  Uniformly tighten the head capscrews, torquing to 25 lbs 

ft (34 Nm). 

35.  Loosen both bearing locknuts (24A). 

36.  Rotate the shaft to test for binding or tight spots. If the 

rotor does not turn freely, tap the rim of the head with a 
soft faced mallet until the correct position is found.  

Figure 8– Locknut Assembly 

LOCKNUT ADJUSTMENT  

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 (71), causing wear.  See Figure 8. 

37.  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.  

38.  Tighten both locknuts (24B) to ensure that the bearings 

(24) are bottomed in the head recess.  DO NOT 
overtighten and bend or shear the lockwasher inner tang.  

39.  Loosen both locknuts (24A) one complete turn.  

40.  Tighten one locknut (24A) until a slight rotor drag is felt 

when turning the shaft by hand.  

41.  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.  

42.  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 “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. 

43.  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 (24A) adjusted 
last. 

44.  Attach the new bearing cover gasket (26) and the bearing 

cover (27) to the non-driven side of pump with the grease 
fitting (76) upward.  Install and tighten the bearing cover 
capscrews (28), torquing to 15 lbs ft (20 Nm). 

45.  Inspect the grease seal (104) in the foot bracket for wear 

or damage and replace as required. Grease the outside 
diameter of the grease seal (104) and push it into the 
bracket (108 or 108B) with the lip inward. 

46.  Mount the assembled pump on the foot bracket (108 or 

108B) with the four mounting screws (28A).   

47.  Reinstall coupling, shaft key, and coupling guards. 

48.  Refer to “Pre-Start Up Check List” and “Start Up 

Procedures” sections of this manual prior to restarting 
pump operation. 

RELIEF VALVE ASSEMBLY  

1.  Insert the valve (9) into the relief valve bore of the casing 

with the small end inward. 

2.  Install relief valve disc (9A) into relief valve. 

3.  Install the relief valve spring (8) in the valve bore. 

4.  Install new O-ring (4A) on spring guide (7). 

5.  Install spring guide (7) in valve bore of cylinder, aligning 

spring (8) on spring guide during assembly. 

6.  Install new O-ring (10) in O-ring groove in relief valve cap 

(4). 

7.  Apply a thin coat of grease on threads of relief valve cap 

(4) and install in cylinder (12). 

8.  Screw the relief valve adjusting screw (2) with locknut (3) 

into the valve cover (4) until it makes contact with the 
spring guide (7). 

9.  After the relief valve has been adjusted, tighten the 

Locknut (3)  

NOTICE: 

The relief valve setting MUST be tested and adjusted 
more precisely before putting the pump into service.  
Refer to "Relief Valve Setting and Adjustment" 
 

10.  Refer to “Pre-Start Up Check List” and “Start Up 

Procedures” sections of this manual prior to restarting 
pump operation. 

Do not operate 

without guard 

in place 

OPERATION WITHOUT GUARDS IN 
PLACE CAN CAUSE SERIOUS 
PERSONAL INJURY, MAJOR 
PROPERTY DAMAGE, OR DEATH. 

Do not operate 

without guard 

in place 

FAILURE TO ADJUST GUARDS 
COVERING ALL ROTATING PART, 
ALLOWING ONLY A SAFE GAP, CAN 
CAUSE PERSONAL INJURY OR DEATH