Pratissoli KT24A Instrucciones de funcionamiento
KT24A/28A/30A/32A/36A/40A
Repair Manual
General Pump is a
member of the
Interpump Group
8
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KT24A, KT28A, KT30A, KT32A, KT36A, KT40A
GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 2
INDEX
1. INTR DUCTI N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 3
2. REPAIR INSTRUCTI NS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 3
2.1 Repairing Mechanical Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 3
2.1.1 Disassembly of Mechanical Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 4
2.1.2 Reassembly of Mechanical Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 6
2.1.3 Increase and Reduction Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 8
2.1.4 Disassembly / Reassembly of Bearings and Shims . . . . . . . . . . . . . .Page 8
2.2 Repairing Hydraulic Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 11
2.2.1 Dismantling the Head-Valve Units . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 11
2.2.2 Reassembling the Head-Valve Units . . . . . . . . . . . . . . . . . . . . . . . . .Page 14
2.2.3 Dismantling the Head-Seals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 15
2.2.4 Dismantling the Piston Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 17
2.2.4 Assembling the Head - Seals - Piston Unit . . . . . . . . . . . . . . . . . . . . .Page 18
3. SCREW CALIBRATI N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 19
4. REPLACING THE C N-R D F T BUSHINGS . . . . . . . . . . . . . . . . . . . . . . . . .Page 20
5. REPAIR T LS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 21
6. MAINTENANCE L G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Page 22
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1. INTR DUCTI N
This manual describes the instructions for repairing KT 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 INSTRUCTI NS
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.
GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 3
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GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 4
2.1.1 Disassembly of Mechanical Parts
The operations described must be performed after removing the hydraulic part, ceramic pistons and
splash guards from the pump (paragraphs 2.2.3, 2.2.4).
Remove in the following order:
• The pump shaft tab
• The rear cover
• The connecting rod cap as follows:
unscrew the cap fixing screws, remove the con-rod caps with their lower half-bearings (fig. 2)
paying atention to the numbered sequence during disassembly.
To avoid possible errors, caps and con-ro shanks have been numbered on one side (1, fig. 2/a).
- Push the piston guides forward with their con-rods to facilitate side extraction of the pump as
indicated in fig. 4.
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- The side covers using - for extraction 3 fully threaed M6 x 50 screws, inserting them in the
threaded holes as indicated in fig. 3
GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 5
• Remove the pump shaft
• Complete the disassembly of the con-rod units by removing them from the pump casing and
removing the piston guide pins
• Remove the pump shaft seal rings using common tools
• Remove the piston guide seal rings as described below:
Use the extractor, p/n F26019400 (1, fig. 5) and the gripper, p/n F27503800 (2, fig. 5). Insert the gripper as
far as possible onto the seal ring with the aid of a hammer (fig. 5/a), subsequently screwing the extractor to
the gripper, and use the extractor hammer (fig. 5/b) until the ring to be replaced is removed (fig. 5/c).
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GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 6
2.1.2 Reassembly of mechanical parts
• Insert the piston/con-rod guide units into the pump casing, directing the numbering on the con-rod
shank towards the top of the casing.
To facilitate pump chaft insertion (without the tab), it is essential to repeat the operation performed during
disassembly, pushing the piston/con-rod guide units as far down as possible (paragraph 2.1.1).
• Before assembling the side cover on the PTO side, check the conditions of the radial ring lip seal
and relative contact area on the shaft.
Make sure that the reference marks on the upper half-bearing (1, fig. 6) and lower half-
bearings (2, fig. 6/a) are positioned in their respective seats in the con-rod and cap.
After having checked that the casing is clean, proceed with assembly of the mechanical part as described
below:
• Assemble the upper and lower half-bearings in their seats in the con-rods and caps.
If replacement is necessary, position the new ring using tool p/n F27904500 as incicated in fig. 7
If the pump shaft shows diametrical wear in the area of contact with the lip seal, in order to
prevent the grinding operation, it is possible to reposition the ring in abutment with the cover
as shown in fig. 7.
Before assembling the side covers, make sure there are O-rings on both of them and shim rings on
the indicator side cover only. To facilitate filling of the first section and relative insertion of the covers on
the casing, we recommend using three partially threaded M6x40 screws (1, fig. 8), then completing the
operation with the screws supplied (M6x16).
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GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 7
Fasten the caps to their respective con-rod shanks by means of M8x1x42 screws (fig. 10) lubricating both the
underhead and the threaded shank, proceeding in two stages:
• Couple the con-rod caps to their shanks, referring to the numbering (1, fig. 9).
Note the correct assembly direction of the caps.
1. Manually turn the screws until they begin to tighten
2. Tightening torque: 22 Ft. Lbs. (30 Nm)
Alternatively, ensure:
1. Pre-tightening torque: 7-11 Ft. Lbs. (10-15 Nm)
2. Tightening torque: 22 Ft. Lbs. (30 Nm)
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• After having completed tightening operations, check that the con-rod head has a side clearance in
both directions.
• Assemble the new piston guide seal ring with the relative seats on the pump casing (fig. 11)
following the procedure described:
Using tool p/n F27904200 composed of a tapered bushing and a buffer, screw the tapered bushing into the
hole in the piston guide (fig. 11a), insert the new seal ring on the buffer as far as it will go (determined by
the height of the buffer) into its seat on the pump casing (fig. 11b), remove the tapered bushing (fig. 11/c).
GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 8
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• Mount the rear cover complete with the O-ring, positioning the dipstick hole upward.
• Insert Oil in the casing as indicated in the use and maintenance manual.
2.1.3 Reduction Classes
TABLE F REDUCTI NS F R CRANKSHAFTS AND C N-R D HALF-BEARINGS
Recovery Classes
(mm)
Part Number
Half-bearing
Upper
Part Number
Half-bearing
Lower
Correction on the Shaft Pin
Diameter
(mm)
0.25 F90922100 F90922400 Ø39.75 0/-0.02 Ra 0.4 Rt 3.5
0.50 F90922200 F90922500 Ø39.50 0/-0.02 Ra 0.4 Rt 3.5
2.1.4 Disassembly/Reassembly of Bearing and Shims
The type of bearings (taper roller) ensures the absence of axial clearance on the crankshaft. The shims are
defined to meet this necessity. For disassembly-reassembly and for any replacements, carefully observe the
following directions:
GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
A) Disassembly/Reassembly of the crankshaft without bearings replacement
After having removed the side covers as indicated in point 2.1.1, check the conditions of the rollers and their
relative tracks. If all parts are in good condition, clean the components carefully with a degreaser and
redistribute lubricant oil uniformly. The previous shims can be reused, taking care to insert them only under
the indicator side cover.
Once the complete unit is mounted (indicator side flange and shaft and motor side flange), check that the
rotation torque of the shaft - with the con-rod disconnected - is a minimum 3 Ft. bs. (4 Nm), max. 4.5 Ft. bs
(6 Nm).
To bring the two side covers closer to the casing, it is possible to use 3 M6x40 screws for the first positioning
phase as indicated in fig. 8 and the screws provide for final fastening.
Shaft rotation torque (with the con-rod connected) should not exceed 6 Ft. b. (8 Nm).
A) Disassembly/Reassembly of the crankshaft with bearings replacement
After removing the side covers, as described above, remove the outer ring nut on the bearings from its seat
on the covers, using an appropriate extractor as shown in fig. 12 and 12a.
Remove the inner ring on the bearings from the two ends of the shaft, again using an appropriate extractor
or, alternatively, a simple “pin punch” as shown in fig. 13.
The new bearings can be mounted cold with a press or rocker, supporting it on the lateral surface of the
ring nuts involved in press fitting with the rings. The press fitting operation can be facilitated by heating the
involved parts to a temperature between 250o-300oF(120o-300o C), ensuring that the ring nuts go down to
end stroke in their housings.
Never exchange the parts of the two bearings.
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GENERAL PUMP A member of the Interpump Group
KT24A/28A/30A/32A/36A/40A SERIES
Page 10
Determining the shim pack:
Perform the operation while the piston/con-rod guide units are assembled, the con-rod caps are disconnected
and the con-rods are pushed downwards. Insert the crankshaft in the casing, checking that the PTO shank
comes out from the provided side. Secure the PTO side flange to the casing, taking care with the lip seal as
described previously and tighten the fixing screws to the recommended torque. Then feed the flange on the
indicator side without shims in the case and start to move it closer, manually screwing the M6x40 service
screws in equally, with small rotations such as to move the cover in slowly and correctly.
At the same time, check that the shaft rotates freely by turning it manually.
Continuing the procedure in this way, a sudden increase in difficulty during shaft rotation will soon be
experienced.
At this point, halt the forward movement of the cover and loosen the fixing screws completely.
With the aid of a thickness gauge, measure the clearance between the side cover and pump casing (fig. 4).
Detected
Measurement
Shim
Type # Pieces
From: 0.05 to: 0.10 / /
From: 0.11 to: 0.20 0.1 1
From: 0.21 to: 0.30 0.1 .2
From: 0.31 to: 0.35 0.25 1
From: 0.36 to: 0.45 0.35 1
From: 0.46 to: 0.55 0.35
0.10
1
1
From: 0.56 to: 0 .60 0.25 2
From: 0.61 to: 0.70 0.35
0.25
1
1
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Once the type and number of shims have been determined using the table, check the following: assemble the
shim pack on the indicator side cover centring (fig. 15), secure the cover to the casing, following the
procedure in paragraph 2.1.2 and tighten the screws to their recommended torque. Check that the shaft
rotation stall torque is between 3-4.5 Ft. bs.(4-6 Nm). If this torque is correct, connect the con-rods to the
crankshaft and to the next stages. If it is not, redefine the shim pack, repeat the operations.
Proceed to detemine the shim pack, using the table below:
Este manual sirve para los siguientes modelos
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