Service guide
PAH, PAHT, PAHT C, PAHT G pumps
PAH 2-6.3/PAHT 2-6.3/PAHT C 2-6.3
and PAHT G 2-6.3
Disassembling and assembling
hpp.danfoss.com
Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
Table of Contents
Contents
Introduction .......................................................................................2
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 / PAHT / PAHT C 2 ...............................................16
4.1 Exploded view for PAH / PAHT / PAHT C 2 ...............................................17
5. Spare parts list for PAHT G 2 ............................................................18
5.1 Exploded view for PAHT G 2 ............................................................19
6. Spare parts list for PAH / PAHT / PAHT C 3.2-6.3 .........................................20
6.1 Exploded view for PAH / PAHT / PAHT C 3.2-6.3 .........................................21
7. Spare parts list for PAHT G 3.2-6.3 ......................................................22
7.1 Exploded view for PAHT G 3.2-6.3 ......................................................23
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 C / PAHT G 2-6.3.
Tools provided with tool set 180Z0235:
• Shaft bush, torpedo
• Press bush Ø18 (Plastic)
2
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
1. Disassembling the
pump
1. Tools required for dismantling.
Caution: Avoid scratching the sealing
surface on the shaft
2. Remove the parallel key and unscrew the
front cover.
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 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
7. Remove the housing. 8. Remove the cylinder barrel.
9. Remove the pistons and the retainer plate
from the cylinder barrel.
NB: Items 10.1.a. and 10.1.b. concern PAH 2, PAHT 2, PAHT C 2 and PAHT G 2 only
10.1.b. Remove the stop.10.1.a. Remove the spring
4
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
NB: Items 10.2.a. through 10.2.c. concern PAH 4-6.3, PAHT 3.2-6.3, PAHT C 3.2-6.3 and
PAHT G 3.2-6.3 only
10.2.a. Remove the retainer guide.
10.2.c. Remove the spring.
10.2.b. Remove the spring guide.
NB: The following items concern PAH 2-6.3, PAHT 2-6.3, Paht C 2-6.3 and
PAHT G 2-6.3 only
11. Loosen the valve plate using two
screwdrivers. Place one of the
screwdrivers in the slot of the valve plate.
180R9094 | 521B0985 | DKCFN.PI.011.N6.02 | 06.2017
12. Remove the valve plate.
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
13. Remove the ve O-rings and the ve
back-up O-rings. 14. Remove the port plate from the ange.
Flange
Front cover
Valve plate
with sealing
15. Wash all parts and replace all seals
(inclusive shaft seal).
17. If the pump has failed, the reason for the
failure must be found and xed before
the repaired pump is re-installed.
16. Inspect all parts carefully
(see “Inspection”) and replace any worn
parts.
Housing with
swash plate
and bearing
Cylinder barrel
Retainer plate
Pistons
Port plate
Spring
Stop
6
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
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 2.85 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.
PAHT only:
It is acceptable that the (black) treated
surfaces of the pistons are partly worn o.
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
2.3. Cylinder barrel
2. Check that the bushings are free from
seizure and large scratches, and ensure
1. Check the outer bearing surface for large
wear grooves (not critical).
2.4. Housing
that the pistons can move freely in the
bushings.
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. Check the bearing (the black part) for
large wear grooves (not critical).
1. Unscrew center bolt from the swash plate.Mounted swash plate:
8
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
Guide pin2. 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 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
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.
10
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
9.1 NB: Items 9.1.a through 9.1.c concern PAH 2, PAHT 2, PAHT C 2 and PAHT G 2 only
9.1.a. Mount the stop.
9.1.b. Mount the spring in the centre hole.
9.1.c. Mount the retainer plate.
9.2 NB: Items 9.2.a through 9.2.d concern PAH 4-6.3, PAHT 3.2-6.3, PAHT C 3.2-6.3
and PAHT G 3.2-6.3 only
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9.2.b. Mount the spring guide.9.2.a. Mount the spring in the centre hole.
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
9.2.c. Mount the retainer guide on the spring
guide.
9.2.d. Mount the retainer plate on the
retainer guide.
9.3 NB: The following items concern PAH 2-6.3, PAHT 2-6.3 and PAHT G 2-6.3 only
11. All pistons inserted.10. Insert the pistons.
12. Place pin and place swash plate ttet on
guide pin and center hole.
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
14. Tighten to a torque of 10 ±1 Nm.13. Place the screw in the center hole.
Alignment
hole
Guide pin
15. Mount the pump housing using the pin
as guide.
16. Press the housing down by hand and
insert the screws.
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18. Mount the two O-rings in the ange and
the O -ring on the front cover.17. Tighten the screws to a torque of 13 Nm.
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
19. Wet the shaft seal with water and mount
it in the front cover. Ensure that it is
pressed to the bottom.
20. Mount the washer with the edge
pointing upwards.
23. Wet the shaft seal and slide it over the
bush.
22. Fit the hollow bush onto the shaft.21. Mount the spring.
24. Use the shaft seal tool when pressing the
shaft seal downwards.
14
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
25. Press the shaft seal in position. 26. Remove the bush.
27. Mount the front cover and align it to the
screw holes. 28. Tighten the screws to a torque of 7 Nm.
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
4. Spare parts list for
PAH / PAHT / PAHT C 2
Pos. Qnt. Designation Material
- 1 Shaft bush, torpedo x x x
- 1 Press bush x
1 1 Housing AISI 304 / PEEK
2 1 Pin AISI 316 x x
5 4 Screw AISI 316 x x
31 1 Swash plate AISI 431 x
32 1 Screw AISI 304 x
33 1 Washer AISI 304 x
34 1 Pin AISI 316 x
61 1 Cylinder barrel AISI 431 / PEEK x x
62 1 Spring AISI 304 x x
63 1 Spring guide PEEK
64 1 Retainer ball PEEK
65 1 Retainer plate 1.4301 x x
66 5 Piston AISI 431/ PEEK x x
67 1 Key AISI 316Ti x x
69 1 Stop PEEK x x
91 1 Port plate AISI 304 / PEEK x x
92 1 Valve plate AISI 431 x x
93 5 Back up ring PTFE x x x x
94 5 O-ring NBR x x* x x
121 1 Port ange AISI 304 / PEEK
122 1 O-ring NBR x
123 1 O-ring NBR x x*
124 1 Shaft seal AISI 304 / NBR x x*
125 1 End cover AISI 304 x*
126 1 Pin AISI 316 x
127 2 Screw M5 x 20 AISI 304 x x
130 1 Usit-ring x x
136 2 O-ring Ø7 x Ø1,5 NBR x x*
1 Service instruction x x x x x x x x x
180B4100 - Seal set
(PAH / PAHT 2-6.3)
180B4572 - Screw & Seal set FFKM
(PAHT c 2-6.3)
180B4112 - Cylinder barrel set
(PAH 2- 6.3)
180B4104 - Cylinder barrel set
(PAHT / PAHT C 2-6.3)
180B4101 - Valve plate set
(PAH / PAHT 2-6.3)
180B4571 - Valve plate set FFKM
(PAHT C 2-6.3)
180B4110 - Piston set
(PAH 2)
180B4102 - Piston set
(PAHT PAHT C 2)
180B4301 - Swash plate set
(PAH / PAHT / PAHT C 2))
180Z0235 - Tool set
* FFKM Sealing material
16
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
4.1 Exploded view for
PAH / PAHT / PAHT C 2
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
5. Spare parts list for
PAHT G 2
Pos. Qnt. 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 316 x
31 1 Swash plate AISI 431 x
32 1 Screw AISI 304 x
33 1 Washer AISI 304 x
34 1 Pin AISI 316 x
61 1 Cylinder barrel AISI 431 / PEEK x
62 1 Spring AISI 304 x
63 1 Spring guide PEEK
64 1 Retainer ball PEEK
65 1 Retainer plate 1.4301 x
66 5 Piston AISI 431/ PEEK x
67 1 Key AISI 316Ti x
69 1 Stop PEEK x
91 1 Port plate AISI 304 / PEEK x
92 1 Valve plate AISI 431 x
93 5 Back up ring PTFE x
94 5 O-ring NBR 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
136 2 O-ring NBR x
180B4307 - Seal set
(PAHT G 2-6.3)
1 Service instruction x x x x x
180B4311 - Cylinder barrel set
(PAHT G 2-6.3)
180B4308 - Valve plate set
(PAHT G 2-6.3)
180B4309 - Piston set
(PAHT G 2)
180B4317 - Swash plate set
(PAHT G 2)
180Z0235 - Tool set
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
5.1 Exploded view for
PAHT G 2
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
6. Spare parts list for
PAH / PAHT / PAHT C 3.2-6.3
180B4100 - Seal set
(PAH / PAHT 2-6.3)
180B4572 - Screw & Seal set
(PAHT C 2-6.3)
180B4112 - Cylinder barrel set
(PAH 2- 6.3)
180B4104 - Cylinder barrel set
(PAHT / PAHT C 2-6.3)
180B4101 - Valve plate set
(PAH 2-6.3 / PAHT 2-6.3)
180B4571 - Valve plate set
(PAHT C 2-6.3)
18 0B 4111- Piston set
(PAH 4-6. 3)
180B4103 - Piston set
(PAHT / PAHT C3.2-6.3)
180B4302 - Swash plate set
Pos. Qnt. Designation Material
- 1 Shaft bush, torpedo - x
- 1 Press bush - x
1 1 Housing AISI 304 / PEEK
2 1 Pin AISI 316 x x
5 4 Screw AISI 316 x x
31 1 Swash plate AISI 431 x x x
32 1 Screw AISI 304 x x x
33 1 Washer AISI 304 x x x
34 1 Pin AISI 316 x x x
61 1 Cylinder barrel AISI 431 / PEEK x
62 1 Spring AISI 304 x x
63 1 Spring guide PEEK x x
64 1 Retainer ball AISI 431 x x
65 1 Retainer plate AISI 431 x x
66 5 Piston AISI 431/ PEEK x x
67 1 Key AISI 316Ti x x
69 1 Stop PEEK
91 1 Port plate AISI 304 / PEEK x x
92 1 Valve plate AISI 431 x x
93 5 Back up ring PTFE x x x x
94 5 O-ring NBR x x* x x
121 1 Port ange AISI 304 / PEEK
122 1 O-ring NBR x x*
123 1 O-ring NBR x x*
124 1 Shaft seal AISI 304 / NBR x x*
125 1 End cover AISI 304
126 1 Pin AISI 316 x x
127 2 Screw AISI 304 x x
130 1 Usit-ring AISI 304 / NBR x x
136 2 O-ring NBR x x*
1 Service instruction - x x x x x x x x x x x
* FFKM seling material
(PAHT / PAHT C 3.2)
180B4303 - Swash plate set
(PAH / PAHT / PAHT C 4)
180B4304 - Swash plate set
(PAH / PAHT PAHT C 6.3)
180Z0235 - Tool set
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
6.1 Exploded view for
PAH / PAHT / PAHT C 3.2-6.3
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
7. Spare parts list for
PAHT G 3.2-6.3
Pos. Qnt. 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 316 x
31 1 Swash plate AISI 431 x x x
32 1 Screw AISI 304 x x x
33 1 Washer AISI 304 x x x
34 1 Pin AISI 316 x x x
61 1 Cylinder barrel AISI 431 / PEEK x
62 1 Spring AISI 304 x
63 1 Spring guide PEEK x
64 1 Retainer ball PEEK x
65 1 Retainer plate 1.4301 x
66 5 Piston AISI 431/ PEEK x
67 1 Key AISI 316Ti x
69 1 Stop PEEK
91 1 Port plate AISI 304 / PEEK x
92 1 Valve plate AISI 431 x
93 5 Back up ring PTFE x
94 5 O-ring NBR 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 1 Usit-ring AISI 304 / NBR x
136 2 O-ring NBR x
1 Service instruction x x x x x x x
180B4307 - Seal set
(PAHT G 2-6.3)
180B4311 - Cylinder barrel set
(PAHT G 2-6.3)
180B4308 - Valve plate set
(PAHT G 2-6.3)
180B4310 - Piston set
(PAHT G 3.2-6.3)
180B4318 - Swash plate set
(PAHT G 3.2)
180B4319 - Swash plate set
(PAHT G 4)
180B4320 - Swash plate set
(PAHT G 6.3)
180Z0235 - Tool set
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Service guide | Disassembling and assembling PAH 2-6.3, PAHT 2-6.3, PAHT C 2-6.3 and PAHT G 2-6.3
7.1 Exploded view for
PAHT G 3.2-6.3
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Danfoss A/S
High Pressure Pumps
Nordborgvej 81
DK-6430 Nordborg
Denmark
© Danfoss | DCS (im) | 2017.06
180R9094 | 521B0985 | DKCFN.PI.011.N6.02 | 24
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