Pratissoli SK Series Operating instructions

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SK Series
Repair Manual
Menu

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INDEX
1. INTRODUCTION 4
2. REPAIR INSTRUCTIONS 4
2.1 Repair of the mechanical part.............................................................................................4
2.1.1 Dismantling the mechanical part........................................................................5
2.1.2 Assembling the mechanical part.......................................................................16
2.1.3 Classes of increase............................................................................................31
2.2 Repair of the hydraulic part ...............................................................................................32
2.2.1 Dismantling the head – liners – valves.............................................................32
2.2.2 Assembling the head – liners – valves..............................................................35
2.2.3 Dismantling the piston – supports – seals assembly........................................36
2.2.4Assembling the piston – supports – seals assembly.........................................38
3. SCREW CALIBRATION 42
4. REPAIR TOOLS 45

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1. INTRODUCTION
This manual contains the instructions for the repair of the SK family of pumps. It must be carefully read and
understood before any operation is carried out on the pump.
The proper functioning and lifetime of the pump depends on correct use and proper maintenance.
Interpump Group declines all responsibility for damage caused due to negligence and/or failure to observe
the instructions described in this manual.
2. REPAIR INSTRUCTIONS
2.1 Repair of the mechanical part
Repairs on the mechanical part must be carried out after removing the oil from the casing.
To remove the oil, remove the oil filling plug pos.c, fig.1 and then the drain plug pos.d, fig.1 present on
both sides of the casing.
The spent oil must be placed in a suitable container and disposed of properly at an
authorised centre.
Do not under any circumstances discard it in the environment.
fig. 1

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2.1.1 Dismantling the mechanical part
The correct sequence is as follows:
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 fig.109).
Remove the upper inspection cover and the lower inspection cover by unscrewing the 4+4 attachment
screws, as shown in point 2.2.3 (fig.120 and fig.121).
Slip off the O-rings and replace them if necessary.
Remove the three pistons with an open-ended spanner, as shown in 2.2.3 (fig.122).
Remove the three spray-guards, complete with O-rings (pos.cand d, fig.2).
Unscrew the M6 locking grub screws from the three oil seal covers (pos.c, fig.3).
fig. 3
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fig. 2
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Take out the oil seal covers by screwing a threaded bar or an extractor M6 screw in the holes in the cover
(pos.c, fig.4) and take out the covers from the pump group (pos.c, fig.5).
Take out the radial seal ring (pos.c, fig.6) and the outside O-ring (pos.c, fig.7).
Remove the lug from the PTO shaft (pos.c, fig.8).
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fig. 8
fig. 4
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fig. 5
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fig. 7
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fig. 6

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Unscrew the attachment screws of the shaft end cover (pos.c, fig.9) and slip the cover off the PTO shaft.
Unscrew the casing cover attachment screws (pos.c, fig.10) and remove it. Slip off the O-ring and replace it
if necessary.
Now remove the two bearing covers by unscrewing the screws (pos.c, fig.11).
To help with their removal, use 2 x M8 grub screws or screws (pos.c, fig.12) as extractors.
Slip off the O-ring and replace it if necessary.
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fig. 9
fig. 11
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fig. 12
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fig. 10

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Insert a shim under the shank of the central connecting rod, to stop the rotation of the crankshaft (pos.c,
fig.13).
Unscrew and take out the bush locking flange attachment screws, from both sides (pos.c, fig.14).
The bush locking flanges must be left in position (pos.c, fig.15).
On one side, screw a ferrule (type SKF KM20) onto the pressure bush (pos.c, fig.16), and then unblock the
bush using a striking hammer (pos.c, fig.17), but do not remove it.
Repeat the operation on the other side.
fig. 14
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fig. 16
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fig. 17
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fig. 13
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fig. 15
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Remove the shim from under the shank of the central connecting rod.
Unscrew the connecting rod screws (pos.c, fig.18).
Dismantle the small ends of the connecting rods with the half-bearings. During this operation take particular
care to note 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.
To prevent any errors, small ends and big end halves are numbered on one side (pos.c, fig.19).
Advance the three big end halves as far as possible in the direction of the head.
Slip off the three upper half-bearings of the big end halves (pos.c, fig.20).
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fig. 18
fig. 19
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fig. 20
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Take out both of the pressure bushes (pos.c, fig.21).
Separate the bush locking flange from the pressure bush (pos.c, fig.22).
Unscrew the screws of the two bearing support covers (pos.c, fig.23).
fig. 21
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fig. 23
fig. 22
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Apply an M16 threaded pin to one end of the crankshaft (pos.c, fig.24) and, while keeping it raised, take out
the bearing support cover complete with bearing and O-ring (pos.c, fig.25). To help with their removal, use
2 x M10 grub screws or screws (pos.d, 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 (pos.c, fig.26).
Unscrew the attachment screws of the left and right PTO bearing cover (pos.c, fig.27) and slip the two
covers off the PTO shaft. To help with their removal, use 3 x M8 grub screws or screws (pos.c, fig.28) as
extractors.
fig. 25
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fig. 27
fig. 26
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fig. 24
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fig. 28
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Take out the radial seal ring (pos.c, fig.29) and the outside O-ring (pos.c, fig.30) and the lubrication hole
O-ring (pos.c, fig.31).
Roll back the three connecting rods as far as possible (until they touch the crankshaft).
Using a striking hammer or mallet (pos.c, fig.32), take out the PTO crankshaft from either one of the two
sides (pos.c, fig.33).
fig. 29
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fig. 32
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fig. 33
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fig. 30
fig. 31
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Slip the internal bearing rings off the PTO shaft (pos.c, fig.34) and also slip off the two internal bearing
spacers (pos.d, fig.34).
The internal and external bearing rings must be reassembled in exactly the same order and
pairings in which they were dismantled.
Using a sufficiently long bar (pos.c, fig.35) and a striking hammer, take the bearing rings out of the pump
casing (pos.c, fig.36), along with the external bearing spacer (pos.c, fig.37) and the bearing lubrication
bush (pos.c, fig.38).
fig. 34
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fig. 35
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fig. 36
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fig. 37
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fig. 38
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Advance the big end halves in the direction of the hydraulic part and lock them in place using the special
device (order code 27566200) (pos.c, fig.39).
Move the crankshaft from the lower part of the casing (pos.c, fig.40).
Proceed to unscrew the screws of the device (order code 27566200) to unlock the connecting rods (pos.c,
fig.41) and then take out the connecting rod/piston head assemblies from the rear opening of the casing
(pos.c, fig.42).
fig. 39
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fig. 40
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1 fig. 41 fig. 42
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Couple the big end halves to the small ends that were previously dismantled, with reference to their
numbering scheme (pos.c, fig.43).
Remove the two pin-locking Seeger rings using the correct tool (pos.c, fig.44).
Slip out the pin (pos.c, fig.45) and take out the connecting rod (pos.c, fig.46).
1 fig. 43
fig. 44
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fig. 45
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fig. 46
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To separate the stem from the piston head, it is necessary to unscrew the hexagonal-head M10 screw using
a no. 17 socket wrench (pos.c, fig.47).
Complete the dissassembly of the mechanical part by removing the oil level lights, the eyebolts and the 90°
quick-fit connection.
2.1.2 Assembling the mechanical part
Proceed with the assembly, following the reverse of the procedure shown in 2.1.1.
The correct sequence is as follows:
Attach the two oil level lights, the two oil drain plugs and the 90° quick-fit connection (pos.c,dand e
fig.48).
fig. 47
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fig. 48
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Connect the stem to the piston head.
Insert the Ø5 roll pin in the hole on the piston head (pos.c, fig.49) and connect the stem to the piston head
using a M10x35 screw (pos.c, fig.50).
Place the stem in a vice, closing the teeth of the vice on the two flat areas, and proceed with setting, using a
torque wrench (pos.c, fig.51) as shown in section 3.
Insert the connecting rod into the piston head (pos.c, fig.46) and then insert the pin (pos.c, fig.45). Apply
the two shoulder Seeger rings using the correct tool (pos.c, fig.44).
Separate the small ends from the big end halves. Correct pairing is ensured by the numbering on one side
(pos.c, fig.43).
After verifying that the casing is perfectly clean, insert the big end half/piston head assembly into the cylinder
tube in the casing (pos.c, fig.42).
The big end half/piston head assembly must be inserted into the housing with the numbering
of the big end halves visible from above.
fig. 49
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fig. 50
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fig. 51

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Lock the three assemblies using the special device (order code 27566200) (pos.c, fig.41).
Insert the crankshaft through the rear opening of the casing and lay it on the bottom.
The crankshaft must be inserted into the casing so that the teeth on the ring bevel gears are
oriented as shown in fig.52.
Pre-assemble the PTO shaft:
Onto the PTO shaft, slip on the 2 internal rings of the bearings (one per side) (pos.c, fig.53).
The internal and external bearing rings must be reassembled in exactly the same order and
pairings in which they were dismantled.
fig. 52
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fig. 53
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From one side of the casing, insert the bearing lubrication bush (pos.c, fig.54) and an external bearing ring
(pos.c, fig.55) using a pad and a mallet or striking hammer.
Remove the device for locking the connecting rods (order code 27566200) (pos.c, fig.41) and roll back the
connecting rods until they touch the crankshaft.
Insert the pre-assembled PTO shaft into the casing (pos.c, fig.56). Insert it from the other side to the side
where the external bearing ring and the bearing lubrication bush were inserted.
The PTO shaft must be inserted into the casing so that the teeth are oriented as shown in
fig.56.
It is easier to insert the PTO shaft completely inside the bearing by applying an M16 screw to the end of the
shaft being inserted, to keep the shaft lifted up (pos.c, fig.57).
fig. 54
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fig. 55
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fig. 56
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fig. 57
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From the side of the casing where the PTO shaft was inserted, proceed to insert the bearing lubrication bush
(pos.c, fig.58) and an external bearing ring (pos.c, fig.59) using a pad and a mallet or striking hammer.
At both sides, insert the internal bearing spacers (pos.c, fig.60) and the external bearing spacers (pos.c,
fig.61).
Insert the internal ring (pos.c, fig.62) and external ring (pos.c, fig.63) of a bearing from one side of the
pump only.
fig. 58
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fig. 59
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fig. 60
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fig. 61
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fig. 62
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fig. 63
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