moyno Version 3, Service Manual

Page 8 

4-28. Seals.

 It is sound practice to always replace grease 

seals (1 and 9, fig. 4-7) whenever drive shaft and tapered 
roller bearings are removed. 
 

4-29. Packing.

 It is sound practice to always replace pack-

ing whenever the pump bearing housing or G3 bearing re-
tainers are disassembled. 
 

4-30. Rotor. 

 
1. To check for excessive wear of rotor (37, fig. 4-7), 

measure the rotor crest-to-crest diameter (see fig. 4-4) and 
compare with the following chart: 

Rotor 

Capacity 

Standard 

*Crest to Crest Dia. (inches) 

008 

2.772 + .000/—.004 

012 

2.676 + .000/—.004 

022 

3.425 + .000/—.004 

036 

4.015 + .000/—.004 

050 

4.015 + .000/—.004 

065 

4.906 + .000/—.004 

090 

4.906 + .000/—.004 

115 

5.709 + .000/—.004 

175 

6.584 + .000/—.004 

335 

5.800 + .000/—.005 

345 

7.260 + .000/—.004 

620 

7.128 + .000/—.005 

800 

9.068 + .000/—.004 

*These dimensions are applicable for AAA  trim codes only. 

Note: The rotor is designated by the third, fourth and fifth 
 

numbers in the Model Number, La., 2G

065

G2. 

 
2.  If the measured crest to crest diameter is within 0.010 

inch of the standard value and is free of deep nicks, gouges, 
or other surface defects, the rotor is re-usable. 

 
3.  Rotors with crest to crest values 0.011 to 0.050 inch 

under the standard values should be replaced. These rotors 
can be renewed by chrome plating to standard dimensions 
provided that: 

a.  The key slots are not excessively worn. 
 
b.  The rotor surface is not cracked, pitted or deeply 

grooved (1/32 inch or more). 

 
c.  The base surface metal is not pitted or corroded. 

 
4.  Rotors may be sent to Moyno or any other competent 

plating shop. Rotors should be stripped and replated to 
standard dimensions, then buffed. 

4-31. Stator.

 A worn stator may appear pitted and gouged, 

or may appear smooth similar to when new. Performance is 
the best measure of rotor to stator fit. If unable to measure 
performance adequately, suspected stator wear can be 
evaluated by a Moyno sales or factory representative. 

 
4-32. All Other Parts.

 Check for cracks, excessive wear, 

damage to threaded holes, burrs, etc. Replace as neces-
sary. Replace O-rings and all gaskets at each disassembly 
and reassembly. 

4-33.  ASSEMBLY OF G2 OPEN THROAT PUMP 

 
Note: In the following G2 assembly instructions, the part  

reference numbers are from fig. 4-7. 

The Moyno 2000 pumps are reassembled in the 

reverse order of dismantling. The following suggestions  
are offered: 

 
1.  While pump is dismantled, check all gaskets, seals, 

packing, and O-rings. Replace all worn items. It is rec-
ommended that the gear joint seals (32), gear joint O-rings 
(24, 38) and stator O-ring (20) be replaced each time either 
of the gear ioints is disassembled. 

 
2. During the assembly process, cleanliness is impor- 

tant. To avoid premature failure, bearings and gear joint 
components must be handled with care and kept clean. 

4-34. Lubrication During Assembly 

Note: 

The bearings are lubricated at the factory, and will 
only need to be re-lubricated when the shaft/bear-
ing assembly is completely removed from pump. 

1. Bearings.

 Pack bearings after installation on 

shaft (Section 4-37). Lubricant should be packed around  
all of the rollers and should completely cover the faces  
of the races. The void inside the spacer between 

the bearings should be filled approximately half 

way with lubricant. 

2. Gear Joints.

 Both gear joints should be packed with 

lubricant during assembly (Sections 4-39 and 4-40). DO 
NOT use zerk fittings to lubricate gear joints after assembly. 
The pipe plugs (C) in the gear joint shells are vent plugs and 
MUST BE REMOVED during assembly of the gear joints to 
allow excess lubricant to vent from the gear joints. 

3. Packing.

 Lubricate packing rings during assembly. 

Additional grease can be added after assembly through  
the zerk fittings installed in the side of the stuffing box. 

4. Approved lubricants: 

CAUTION:  Do not mix different brands of lubricants for 

the same application. 

Area to Lubricate 

Approved Lubricant or Equivalent 

Bearings, Gear Joints 

& Packing 

ACG-2 

(Dubois Chemical, Inc.) 

 
4-35. Packing Installation 

 
1.  The standard packing set (10) consists of six braided 

packing rings and two teflon lantern ring halves (13). 

 
2.  Install packing and lantern ring halves into the stuffing 

box area of the suction housing (19) in the following se-
quence: 

a.  Wipe a film of lubricant on each packing ring and 

install three rings. Push each ring firmly in place. 

Note:  Install the packing rings with the splits staggered at 90 

degrees to the adjacent ring of packing. On initial as-
sembly, one ring of packing may not fit in stuffing box. 
This final ring of packing should be installed after 
pump is started and packing is seated.