BLACKMER SNP1.25, Installation, Operation And Maintenance Instructions

104-A00    Page 9/16 

MAINTENANCE 

PUMP DISASSEMBLY 

NOTICE: 

Follow all hazard warnings and instructions provided in 
the “Maintenance” section of this manual. 

NOTE: 

The numbers in parentheses following individual parts 

indicate reference numbers on the Pump Parts List. 

1.  On the outboard (non-driven) side of the pump, remove 

the head capscrews (21A), head (23) and disc (71). 
Avoid damaging the head seal ring (72) and disc (71). 

NOTE: 

The sleeve bearing (bushing) (24) is press fit into 

the head and should not be removed unless replacement 
is necessary (see "Sleeve Bearings"). 

2.  Turn the shaft by hand until a vane (14) comes to the top 

(12 o'clock) position of the rotor.  Remove each vane in 
turn. 

3.  On the opposite (inboard) end of the pump, clean the 

pump shaft thoroughly, making sure the shaft is free of 
nicks, burrs, or paint that might damage the packing or 
mechanical seal when the inboard head is removed. 

4. 

PUMPS EQUIPPED WITH PACKING

a.  Remove the packing locknuts (18), studs (17) and 

packing follower (75). 

b.  Remove the head capscrews (21), bracket (108), 

head (20) and disc (71). Avoid damaging the head 
seal ring (72) and disc (71). 

NOTE: 

The sleeve 

bearing (24) is press fit into the head and should not 
be removed unless replacement is necessary (see 
"Sleeve Bearings"). 

c. 

The packing rings (19) and packing washer (58) can 
be pulled from the inboard hub with the use of a 
corkscrew tool or screwdriver. 

F i g u r e   6   –   C o m m e r c i a l   M e c h a n i c a l   S e a l  

5. 

PUMPS EQUIPPED WITH BLACKMER TRIPLE-LIP 
SEAL OR A COMMERCIAL MECHANICAL SEAL

a.  Loosen all setscrews before removing the head 

assembly. For further instructions on the 
disassembly and assembly of commercial 
mechanical seals, refer to the separate literature 
accompanying the seal. 

b.  Remove the head capscrews (21), bracket (108), 

head (20) and disc (71). Avoid damaging the head 
seal ring (72) and disc (71). 

NOTE: 

The sleeve 

bearing (24) is press fit into the head and should not 
be removed unless replacement is necessary (see 
"Sleeve Bearings"). 

6.  From the driven side of the pump, grasp the rotor in the 

3 and 9 o'clock positions, and gently pull the rotor and 
shaft (13) out of the cylinder. 

CAUTION: 

Use care to 

avoid injury-the rotor and shaft is heavy and may have 
sharp edges. 

PARTS REPLACEMENT 

1.  If any of the O-rings have been removed or disturbed 

during disassembly, they must be replaced with new O-
rings. 

NOTE: 

PTFE O-rings should be heated in hot 

water to aid installation. 

2.  Excessive or continuous leakage around the pump shaft 

may be an indication of a damaged mechanical seal, 
worn packing, or a damaged or worn sleeve bearing. 
a.  If a mechanical seal has been leaking, it is 

recommended the entire seal be replaced. Refer to 
"General Pump Troubleshooting" for possible 
causes of seal leakage. 

b.  If the packing is leaking excessively, refer to 

"Packing Adjustment." If this does not solve the 
problem, a complete new set of packing rings 
should be installed. 

c. 

If the pump shaft indicates an excessive amount of 
radial "play," the sleeve bearing in the hub should be 
replaced. 

3.  Worn or scored discs may be reused if interchanged 

from one head to the other with the new side toward the 
rotor.