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4.4 Assembly 4. Maintenance
4.4.9 Fitting primary seals
Step 1
Refer to section 4.5 for seal fitting instructions.
4.4.10 Fitting rotors
Step 1
1. Fit new rotor O rings (18).
2. Fit rotors (17) onto the shafts (24 and 25) with both
dimpled rotor master lobes in the 6 -12 o’clock
position (horizontally ported pumps) or 3-9 o’clock
position (vertically ported pumps).
For Bi-lobe rotors:
Fit one rotor in the 6 - 12 o’ clock plane onto the top shaft and
the remaining rotor in the 3 - 9 o’clock plane on the bottom shaft.
Rotate pump one full revolution ensuring there is no rotor
contact.
Step 2
Fit new O rings (20) to rotor retention nuts (22).
Use a wooden/plastic block between the rotors to stop them
turning whilst tightening the rotor retention nuts to the
recommended torque settings shown in Technical Data (chapter
5).
Step 3
To check rotors are correctly synchronised turn the drive shaft (24) by hand and check meshing clearances with feeler gauges against
recommended clearance figures.
4.4.11 Fitting rotorcase cover
1. Lightly smear new O-ring (11) in grease and fit to rotorcase
cover (12).
2. Fit rotorcase cover onto rotorcase (9) and tighten rotorcase
cover nuts (13).
3. Refer to pump start up checks prior to operation.
