General Pump SK Repair Manual
S
8
S
K
K
Repair Manual
General Pump is a
member of the
Interpump Group
GENERAL PUMP
INDEX
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 3
2. REPAIR INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 3
2.1 Repairing Mechanical Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 3
2.1.1 Disassembly of Mechanical Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 4
2.1.2 Assembly of Mechanical Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 15
2.1.3 Increase and Reduction Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 30
2.2 Repairing Hydraulic Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 31
2.2.1 Dismantling the Head-Liners-Valves . . . . . . . . . . . . . . . . . . . . . . . . . .Page 31
2.2.2 Assembling the Head-Liners-Valves . . . . . . . . . . . . . . . . . . . . . . . . . .Page 34
2.2.3 Dismantling the Plunger Unit-Supports-Seals . . . . . . . . . . . . . . . . . . .Page 35
2.2.4 Assembling the Plunger Unit-Supports-Seals . . . . . . . . . . . . . . . . . . .Page 37
3. SCREW CALIBRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 41
4. REPAIR TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 43
5. MAINTENANCE LOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 44
A member of the Interpump Group
SK SERIES
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GENERAL PUMP
A member of the Interpump Group
SK SERIES
1. INTRODUCTION
This manual describes the instructions for Repairing SK Series pumps, and must be carefully read and
understood before performing any repair intervention on the pump. {proper pump operation and longevity
depend on the correct use and maintenance. General Pump declines any responsibility for
damage caused by the misuse or the non-observance of the instructions described in this manual.
2. REPAIR INSTRUCTIONS
2.1 Repairing Mechanical Parts
Mechanical parts repair must be performed after removal of oil from the casing. To drain
the oil, remove the oil dipstick, (1, fig. 1) and then the draining plug (2, fig. 1).
The oil must be placed in a suitable container and disposed of in special centers.
It absolutely must not be discarded into the environment.
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GENERAL PUMP
2.1.1 Disassembly of Mechanical Parts
The correct sequence is the following:
Completely empty the pump of oil, as indicated in 2.1.
Separate the head and the spacer for liners from the pump casing as shown in 2.2.1 (from fig. 106 to 109).
Remove the upper inspection cover and the lower inspection cover by unscrewing the 4 attachment screws,
as shown in point 2.2.3 (fig. 120 and fig. 121). Slip off the O-rings and replace them in necessary.
Remove the three plungers with an open-ended wrench, as shown in 2.2.3 (fig. 122).
Remove the three spray guards, complete with O-rings (1 and 2, fig. 2).
A member of the Interpump Group
SK SERIES
Unscrew the M6 locking grub screws from the three oil seal covers (1, fig. 3).
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GENERAL PUMP
Take out the oil seal covers by screwing a threaded bar or an extractor M6 screw in the holes in the cover
(1, fig. 4) and take out the covers from the pump group (1, fig. 5).
Take out the radial seal ring (1, fig. 6) and the outside O-ring (1, fig. 7).
A member of the Interpump Group
SK SERIES
Remove the lug from the PTO shaft (1, fig. 8).
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GENERAL PUMP
Unscrew the attachment screws of the shaft end cover (1, fig. 9) and slip the cover off the PTO shaft
Unscrew the casing cover attachment screws (1, fig. 10) and remove it. Slip off the O-ring and replace if needed.
A member of the Interpump Group
SK SERIES
Now remove the two bearing covers by unscrewing the screws (1, fig. 11). To help with their removal, use 2
M8 grub screws (1, fig. 12) as extractors. Slip off the O-ring and replace if necessary.
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GENERAL PUMP
Insert a shim under the shank of the central connecting rod, to stop the rotation of the crankshaft (1, fig. 13).
Unscrew and take out the bush locking flange attachment screws, from both sides (1, fig. 14). The bush
locking flanges must be left in position (1, fig. 15).
A member of the Interpump Group
SK SERIES
On one side, screw a ferrule (type SKF KM20) onto the pressure bushing (1, fig. 16) and then unblock the
bushing using a striking hammer (1, fig. 17) but do not remove it. Repeat the operation on the other side.
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GENERAL PUMP
Remove the shim from under the shank of the central connecting rod. Unscrew the connecting rod screws
(1, fig. 18).
Dismantle the small ends of the connecting rods with the half-bearings. During this operation take particular
care to not the order in which the parts are removed.
The connecting rod small ends and the big end halves must be reassembled in exactly the
same order and pairings in which they were dismantled.
A member of the Interpump Group
SK SERIES
To prevent any errors, small ends and big end halves are numbered on one side (1, fig. 19).
Advance the three big end halves as far as possible in the direction of the head. Slip off the three upper halfbearings of the big end halves (1, fig. 20).
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GENERAL PUMP
Take out both of the pressure bushing (1, fig. 21).
Separate the bushing locking flange from the pressure bushing (1, fig. 22).
A member of the Interpump Group
SK SERIES
Unscrew the screws of the two bearing support covers (1, fig. 23).
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GENERAL PUMP
Apply an M16 threaded pin to one end of the crankshaft (1, fig. 24) and, while keeping it raised, take out the
bearing support cover complete with bearing and O-ring (1, fig. 25). To help with their removal, us 2 M10
grub screws (2, fig. 24) as extractors. Repeat the operation on the other side.
Lay the crankshaft on the bottom of the casing. Separate the bearing support cover from the bearing, using
a striking hammer (1, fig. 26).
A member of the Interpump Group
SK SERIES
Unscrew the attachment screws of the left and right PTO bearing cover (1, fig. 27) and slip the two covers
off the PTO shaft. To help with their removal, use 3 M8 grub screws or screws (1, fig. 28) as extractors.
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GENERAL PUMP
Take out the radial seal ring (1, fig. 29) and the outside O-ring and the lubrication hole O-ring (1, fig. 31).
A member of the Interpump Group
SK SERIES
Roll back the three connecting rods as far as possible (until they touch the crankshaft). Using a striking
hammer or mallet (1, fig. 32), take out the PTO crankshaft from either one of the two sides (1, fig. 33).
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GENERAL PUMP
Slip the internal bearing rings off the PTO shaft (1, fig. 34) and also slip off the two internal bearing
spacers (1, fig. 34).
The internal and external bearing rings must be reassembled in exactly the same order and
pairings in which they were dismantled.
A member of the Interpump Group
SK SERIES
Using a sufficiently long bar (1, fig. 35) and a striking hammer, take the bearing rings out of the pump casing
(1, fig. 36), along with the external bearing spacer (1, fig. 37) and the bearing lubrication bushing (1 fig. 38).
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GENERAL PUMP
Advance the big end halves in the direction of the hydraulic part and lock them in place using the special
tool (part #F27566200) (1, fig. 39).
Move the crankshaft from the lower part of the casing (1, fig. 40).
A member of the Interpump Group
SK SERIES
Proceed to unscrew the screws of the tool (#F27566200) to unlock the connecting rods (`, fig. 41) and then
take out the connecting rod/piston head assemblies from the rear opening of the casing (1, fig. 42).
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GENERAL PUMP
Couple the big end halves to the small ends that were previously dismantled, with reference to their
numbering scheme (1, fig. 43).
Remove the two pin-locking Seeger rings using the correct tool (1, fig. 44).
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SK SERIES
Slip out the pin (1, fig. 45) and take out the connecting rods (1, fig 46).
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