Servie guide
PAH, PAHT, PAHT G pumps
PAH 10-12.5, PAHT 10-12.5 and
PAHT G 10-12.5
Disassembling and assembling
hpp.danfoss.com
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
Table of Contents 1. Disassembling the pump ...................................................................................................................3
2. Inspection ............................................................................................................................................7
2.1. Port plate and valve plate .................................................................................................................7
2.2. Pistons ....................................................................................................................................................7
2.3. Cylinder barrel ..................................................................................................................................... 8
2.4. Housing ..................................................................................................................................................8
2.5. Swash plate ..........................................................................................................................................8
3. Assembling ...........................................................................................................................................9
4. Spare parts list for PAH 10-12.5 / PAHT 10-12.5 ...........................................................................15
4.1. Exploded view PAH 10-12.5 / PAHT 10-12.5 ..................................................................................16
5. Spare parts list for PAHT G 10-12.5 .................................................................................................17
5.1. Exploded view PAHT G 10-12.5 .......................................................................................................18
Introduction
NOTE: If the pump is disassembled within the warranty period, the pump is no longer covered
by the warranty.
This document covers the instructions for
disassembling and assembling the axial piston
pumps PAH / PAHT / PAHT G 10-12.5.
Tools provided with tool set 180Z0235:
• Shaft bush, torpedo
• Press bush ø18 (Plastic)
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
1. Disassembling the
pump
2. Remove the parallel key and unscrew the
front cover.1. Tools required for dismantling.
4. Remove the shaft seal using two
screw drivers.
Caution: Avoid scratching the sealing
3. Dismantle the front cover using a vice.
surface on the shaft.
5. Remove the two small O-rings from the
ange. Remove the seal from the front
cover using a screwdriver. 6. Unscrew the four screws for the housing.
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
7. Remove the housing. 8. Remove the cylinder barrel.
9. Remove the pistons and the retainer plate
from the cylinder barrel.
10. Remove the retainer guide.
12. Remove the spring.11. Remove the spring guide.
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
13. Loosen the valve plate using two
screwdrivers. Place one of the
screwdrivers in the slot of the valve plate.
14. Remove the valve plate.
15. Remove the ve O-rings and the ve
back-up O-rings. 16. Remove the port plate from the ange.
17. Wash all parts and replace all seals
(inclusive shaft seal).
18. Inspect all parts carefully (see
and replace any worn parts.
“Inspection”
19. If the pump has failed, the reason for the
failure must be found and xed before the
repaired pump is re-installed.
)
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
Flange
Housing with
swash plate
and bearing
Retainer plate
Pistons
Spring
Plugs
Front cover
Front
cover crews
Valve plate with
sealing
Spring guide
Retainer guide
Cylinder barrel
Shaft seal
Port plate
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
2. Inspection 2.1. Port plate and valve plate
2. Hold a ruler against the surface of the
1. Neither port plate nor valve plate must
show any sign of wear.
plates and check the tightness against a
light source.
3. Check that both O-rings and back-up rings
are not broken and do not show severe
wear.
2.2. Pistons
1. The play in the ball and socket joint must
not exceed 0.1 mm.
2. The thickness of the piston shoes must be
at least 4.1 mm.
3. Hold a ruler against the surfaces of the
piston shoes to check that the surfaces
are even and smooth and without any
scratches.
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
2.3. Cylinder barrel
2. Check that the bushings are free from
seizure and large scratches.
3. Ensure that the pistons can move freely in
the bushings.
1. Check the outer bearing surface for large
wear grooves (not critical).
2.4. Housing
2. Check the bearing (the black part) for
large wear grooves (not critical).
1
2
1. Check that the swash plate surface is
smooth and without any big scratches
(depth more than 0.1 mm).
2.5. Swash plate
2. Unscrew center bolt from the swash plate.1. Mounted swash plate:
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
Guide pin1. Remove swash plate and guide pin.
3. Assembling
WARNING:
Do not use silicone when assembling the
pump. Do not reuse disassembled O-rings;
they might be damaged. Always use new
O-rings.
1. Lubrication:
• To prevent seizing-up, lubricate all
threads with PTFE lubrication type.
• O-rings inside pump may be lubricated
only with clean ltered water.
• O-rings for port ange, mounting ange
and ushing valve must be lubricated.
• It is important to lubricate ALL parts to
be assembled with clean ltered water
(Especially all PEEK parts).
Important:
It is essential that the pump is serviced in
conditions of absolute cleanliness. All parts
must be absolute clean before mounting.
2. Parts and tools required for assembly.
Check that all parts are OK. Replace all
seals.
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
Guide pin
4. Mount the port plate in its right position
using the pin as guide.3. Mount the O-ring on the ange.
5. Mount the valve plate with seals on the
cylinder barrel.
7. Check that the gap between the cylinder
barrel and the valve plate is 1.5-2.5 mm.
6. Press the valve plate into the cylinder
barrel using a piece of plastic.
8. Mount the cylinder barrel in the ange.
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
10. Mount the spring guide.9. Mount the spring in the centre hole.
11. Mount the retainer guide on the spring
guide.
12. Mount the retainer plate on the retainer
guide. Ensure that the bended surface
points downwards.
14. All pistons inserted.13. Insert the pistons.
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
15. Place pin and place swash plate ttet on
guide pin and center hole.
Alignment
hole
Guide pin
18. Mount the pump housing using the pin as
guide.
17. Tighten to a torque of 10 ±1 Nm.16. Place the screw in the center hole.
19. Press the housing down by hand and
insert the screws.
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
21. Mount the two O-rings in the ange and
the O -ring on the front cover.20. Tighten the screws to a torque of 22 Nm.
22. Wet the shaft seal with water and mount it
in the front cover. Ensure that it is pressed
to the bottom.
23. Mount the washer with the edge pointing
upwards.
25. Fit the hollow bush onto the shaft.24. Mount the spring.
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
26. Wet the shaft seal and slide it over the
bush.
27. Use the shaft seal tool when pressing the
shaft seal downwards.
28. Press the shaft seal in position. 29. Remove the bush.
30. Mount the front cover and align it to the
screw holes. 31. Tighten the screws to a torque of 7 Nm.
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
4. Spare parts list for
PAH 10-12.5 / PAHT 10-12.5
Pos. Qty. Designation Material
- 1 Shaft bush, torpedo - X
- 1 Press bush - X
1 1 Housing AISI 304 / PEEK
2 1 Pin AISI 316 X
5 4 Screw AISI 304 X
31 1 Swash plate AISI 431 X X
32 1 Screw AISI 304 X X
33 1 Washer AISI 304 X X
34 1 Pin AISI 316 X X
61 1 Cylinder barrel AISI 431 / PEEK X X
62 1 Spring AISI 316Ti X X
63 1 Spring guide PEEK X X
64 1 Retainer ball PEEK X X
65 1 Retainer plate AISI 304 X X
66 5 Piston AISI 431/ PEEK X X
67 1 Key AISI 316Ti X
91 1 Port plate AISI 304 / PEEK X
92 1 Valve plate AISI 431 X
93 5 Back up ring PTFE X X
94 5 O-ring NBR X X
121 1 Port ange AISI 304 / PEEK
122 1 O-ring NBR X
123 1 O-ring NBR X
124 1 Shaft seal AISI 304 / NBR X
125 1 End cover AISI 304
126 1 Pin AISI 316
127 2 Screw AISI 304 X
130 2 O-ring NBR X
135 1 Pin AISI 316 X
136 2 O-ring NBR X
- 1 Service instruction (180R9095) - X X X X X X X X
180B4105 - Seal set
(PA HT 10 -12. 5)
180B4107 - Cylinder barrel set
(PA HT 10 -12. 5)
180B4113 - Cylinder barrel set
(PA H 10-12.5)
180B4108 - Valve plate set
(PA HT 10 -12. 5)
180B4106 - Piston set
(PA HT 10 -12. 5)
180B4114 - Piston set
(PA H 10-12.5)
180B4305 - Swash plate set
(PAH T 10)
180B4306 - Swash plate set
(PA HT 12 . 5)
180Z0235 - Tool set
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
4.1. Exploded view
PAH 10-12.5 / PAHT 10-12.5
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
5. Spare parts list for
PAHT G 10-12.5
Pos. Qty. Designation Material
- 1 Shaft bush, torpedo - X
- 1 Press bush - X
1 1 Housing AISI 304 / PEEK
2 1 Pin AISI 316 X
5 4 Screw AISI 304 X
31 1 Swash plate AISI 431 X X
32 1 Screw AISI 304 X X
33 1 Washer AISI 304 X X
34 1 Pin AISI 316 X X
61 1 Cylinder barrel AISI 431 / PEEK X
62 1 Spring AISI 316Ti X
63 1 Spring guide PEEK X
64 1 Retainer ball PEEK X
65 1 Retainer plate AISI 304 X
66 5 Piston AISI 431/ PEEK X
67 1 Key AISI 316Ti X
91 1 Port plate AISI 304 / PEEK X
92 1 Valve plate AISI 431 X
93 5 Back up ring PTFE X X
94 5 O-ring NBR X X
121 1 Port ange AISI 304 / PEEK
122 1 O-ring NBR X
123 1 O-ring NBR X
124 1 Shaft seal AISI 304 / NBR X
125 1 End cover AISI 304
126 1 Pin AISI 316
127 2 Screw AISI 304 X
130 2 O-ring NBR X
135 1 Pin AISI 316 X
136 2 O-ring NBR X
- 1 Service instruction (180R9095) - X X X X X X
180B4312 - Seal set
(PAHT G 10-12.5)
180B4315 - Cylinder barrel set
(PAHT G 10-12.5)
180B4313 - Valve plate set
(PAHT G 10-12.5)
180B4314 - Piston set
(PAHT G 10-12.5)
180B4321 - Swash plate set
(PAHT G 10)
180B4322 - Swash plate set
(PAHT G 12.5)
180Z0235 - Tool set
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Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
5.1. Exploded view
PAHT G 10-12.5
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180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
Service guide | Disassembling and assembling PAH 10-12.5, PAHT 10-12.5 and PAHT G 10-12.5
180R9095 | 521B0986 0 | DKCFN.PI.010.NA4.02| 06. 2017
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Danfoss A/S
High Pressure Pumps
Nordborgvej 81
DK-6430 Nordborg
Denmark
© Danfoss | DCS (im) | 2017.06
180R9095 | 521B0986 | DKCFN.PI.010.NA4.02 | 20
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