Crankcase disassembly – Great Plains CDS-JohnBlue NGP Series Pumps User Manual

Page 12

CRANKCASE DISASSEMBLY

Major pump repair requires some in-depth knowledge on working tolerances for internal parts. We recommend

that you contact your nearest CDS-John Blue sales and service dealer for best results in major pump repair.

Shaft oil seals have been upgraded from previous L & LM series pumps to include a wiper ring. The oil seals

are enclosed in a greaseable cavity to flush debris from around the seal, which is a contributing factor to pre-

mature oil seal failure. The oil seals may be replaced by following the OUTBOARD & INBOARD

COMPONENTS section below. All instruction and visual representation in this section is shown with wet-end

components removed which is covered in the maintenance sections preceding this section.

OUTBOARD COMPONENTS

 Remove the retaining ring, pump setting hub, and pointer.
 Remove the flange cover exposing the oil seal in its cavity.
 Remove the oil seal which may be done with a screw

driver, taking care not to scar the internal shaft or housing.

 Inspection of the stroke setting sleeve should be made for

wear at the seal location as well as the flange gasket for

tears prior to re-assembly.

INBOARD COMPONENTS

 Remove the sprocket from shaft and sprocket spacer,

inspecting the o-ring and thrust washer for wear, cuts, or

damage and replace as necessary.

 Remove the cover plate. It may be necessary to remove

any marks in the crankshaft from the sprocket / spacer

set-screws with a light emery cloth in order for the cover

plate to slip off with the bearing.

 Remove the oil seal with a screw driver, taking care not to

scar the housing or shaft.

 If only the oil seal is being replaced, the cover plate should be re-installed first, then the oil seal. Inspect

the shaft for wear at the seal location, as well as the cover plate gasket for tears, replace as necessary.

INTERNAL COMPONENTS

The following inspection points should be made prior to disassembly if required:

 With inboard and outboard components removed, examine for sediment in the crankcase. A small

amount of metal wear and ‘grit’ in the oil is normal, large sediment may require further disassembly.

 Check for metal and/or fertilizer discoloration to the oil. If fertilizer is present, the crankcase should be

disassembled and each component examined for rust pitting or deterioration.

 Holding the crankcase firmly, take hold of the connecting rod and push / pull. If you feel obvious end

play, disassemble all components and inspect for wear, particularly the eccentrics and connecting rod.