Page 1
Service guide
PAHT / PAHT G pumps
PAHT 20-32 / PAHT G 20-32
Disassembling and assembling
hpp.danfoss.com
Page 2
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
Table of Contents
Introduction
1. Disassembling the pump ..................................................................................................................................... 3
2. Inspection .................................................................................................................................................................. 9
2.1. Valve and thrust plate: .......................................................................................................................................... 9
2.2. Swash plate: .............................................................................................................................................................. 9
2.3. Pistons: ......................................................................................................................................................................10
3. Assembling ............................................................................................................................................................. 11
4. Spare parts list for PAHT 20-32 ........................................................................................................................20
5. Exploded view PAHT 20-32 ...............................................................................................................................21
6. Spare parts list for PAHT G 20-32 ....................................................................................................................22
7. Exploded view PAHT G 20-32 ...........................................................................................................................23
8. Tool sets ....................................................................................................................................................................24
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
PAHT / PAHT G 20-32.
2
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 3
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
1. Disassembling the
pump
2. Loosen and remove 6 screws.1. Tools required for dismantling the pump.
4. Remove shaft sealing.
Caution: Avoid scratching the sealing
3. Remove mounting ange.
surface on the shaft.
5. Remove spring. 6. Remove 2 guide pins.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
3
Page 4
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
7. Remove O-ring. 8. Turn pump upside down.
9. Loosen and remove 10 screws. 10. Remove cover.
11. View to pistons and retainer plate.
12. Remove pistons and retainer plate.
4
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 5
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
13. Remove retainer ball. 14. Remove retainer.
15. Remove spring. 16. Remove cylinder barrel.
18. Remove 1 guide pin.17. Remove port plate.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
5
Page 6
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
19. Turn pump upside down. Loosen and
remove 4 screws. 20. Remove port ange.
21. Remove 1 guide pin.
23. Loosen thrust plate from cylinder barrel.
22. Remove O-ring from port ange.
24. Remove thrust plate.
6
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 7
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
25. Remove O-rings from thrust plate.
27. Remove 1 guide pin from end cover
plate.
26. Remove backup rings from thrust plate.
28. Loosen and remove screw from swash
plate.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
30. Remove 2 guide pins from end cover
plate.29. Remove swash plate.
7
Page 8
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
31. Remove O-ring from end cover plate.
33.
32. Remove shaft sealing from mounting
ange.
34. Pump
disassembled.
8
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 9
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
2. Inspection
2.1. Valve and thrust plate:
1. Neither valve plate nor thrust plate must
show any sign of wear. .
2. Hold a ruler against surface of plate and
check 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. Swash plate:
1. Check that surface of swash plate is
smooth and without any large scratches
(depth more than 0.1 mm)..
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
9
Page 10
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
2.3. Pistons:
1. Play in ball and socket joint must not
exceed 0.1 mm.
2. Thickness of piston shoes must be at least
4.1 mm.
4. Check bushes in cylinderbarrel for wear
and scratches.
3. Hold a ruler against surfaces of piston
shoes to check that the surfaces are even
and smooth and without any scratches. It
is acceptable that the (black) treated
surfaces of the pistons are partly worn..
5. Check main bearing for wear and
scratches.
10
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 11
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
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.
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.
1. Tools required for assembly of the pump. 2. Parts needed for assembly of the pump.
3. Mount 1 guide pin in housing. 4. Mount O-ring in port plate.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
11
Page 12
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
5. Mount port ange on housing. Use pin as
guide. 6. Mount 4 screws (M8x50).
7. Tighten screws to 30Nm.
9. Mount 1 guide pin inside the housing on
the back side of the port plate.
8. Turn pump upside down.
10. Mount port plate. Be aware of
orientation/ guide pin.
12
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 13
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
11. Mount backup rings on the thrust plate.
13. Spray with water on cylinder barrel and
thrust plate.
12. Mount O-rings on the thrust plate.
14. Mount thrust plate on cylinder barrel.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
16. Mount cylinder barrel in housing.15. Press thrust plate into cylinder barrel.
13
Page 14
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
17. Mount spring. 18. Mount retainer on top of the spring.
19. Spray with water and mount retainer ball.
21. Spray with water and mount pistons.
20. Place retainer plate on top of retainer
ball.
22. Spray with water and mount O-ring on
end cover.
14
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 15
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
23. Mount 2 guide pins on endcover.
25. Mount screw (M8x16).
24. Mount swash plate.
26. Tighten screw to 30Nm.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
28. Spray piston shoes with water.27. Mount 1 guide pin on housing.
15
Page 16
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
29. Mount endcover on the housing. 30. Mount 10 screws (M8x16).
31. Tighten 10 screws to 30Nm.
33. Spray with water and mount O-ring.
32. Turn pump upside down and mount 2
guide pins.
34. Spray shaft sealing with water before
mounting.
16
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 17
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
35. Use tool and press shaft sealing into
place.
36. Mount metal ring.
37. Mount spring.
38. Mount special tool on shaft.
40. Mount sealing (smallest diameter
pointing down).39. Spray with water.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
17
Page 18
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
41. Mount mounting ange. 42. Mount 6 screws.
43. Tighten screws to 30Nm.
18
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 19
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
Finished.
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
19
Page 20
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
4. Spare parts list for
PAHT 20-32
Pos. Qnt. Designation Material
1 1 Housing AISI 316
2 2 Pin Ø4 x 14 AISI 304 x
5 10 Screw M8 x 16 AISI 304 x
9 1 O-ring Ø102 x 3 NBR x
11 1 End cover CW AISI 316
31 1 Swash plate AISI 431 x x x
32 1 Screw Ø8 x 16 AISI 304 x x x
34 2 Pin Ø4 x 14 AISI 304 x x x
61 1 Cylinder barrel AISI 431 x
62 1 Spring AISI 304 x
63 1 Retainer PEEK x
64 1 Retainer ball AISI 304 x
65 1 Retainer plate 1.4301 x
66 9 Piston AISI 431 / PEEK x
67 1 Key 8 x 7 x 32 AISI 316Ti x
91 1 Port plate AISI 304 / PEEK x
92 1 Valve plate AISI 431 x
93 9 Back up ring PTFE x
94 9 O-ring Ø13 x 2 NBR x
121 1 Port ange AISI 316
122 1 O-ring Ø102 x 3 NBR x
123 1 O-ring Ø59,5 x 3 NBR x
124 1 Shaft sealing AISI 304 / NBR x
125 1 End cover AISI 316
126 1 Pin Ø5 x 10 AISI 304 x
127 6 Screw M8 x 60 AISI 304 x
128 4 Screw M8 x 50 AISI 304 x
1 Service instruction x x x x x x x
180B4055 - Seal set
(PAHT 20-32)
180B4054 - Cylinder barrel set
(PAHT 20-32)
180B4052 - Valve plate set
(PAHT 20-32)
180B4053 - Piston set
(PAHT 20-32)
180B4251 - Swash plate set
(PAHT 20)
180B4254 - Swash plate set
(PAHT 25)
180B4257 - Swash plate set
(PAHT 32)
20
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 21
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
5. Exploded view
PAHT 20-32
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
21
Page 22
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
6. Spare parts list for
PAHT G 20-32
Pos. Qnt. Designation Material
1 1 Housing AISI 316
2 2 Pin Ø4 x 14 AISI 304 x
5 10 Screw M8 x 16 AISI 304 x
9 1 O-ring Ø102 x 3 NBR x
11 1 End cover CW AISI 316
31 1 Swash plate AISI 431 x x x
32 1 Screw Ø8 x 16 AISI 304 x x x
34 2 Pin Ø4 x 14 AISI 304 x x x
61 1 Cylinder barrel AISI 431 x
62 1 Spring AISI 304 x
63 1 Retainer PEEK x
64 1 Retainer ball AISI 304 x
65 1 Retainer plate 1.4301 x
66 9 Piston AISI 431 / PEEK x
67 1 Key 8 x 7 x 32 AISI 316Ti x
91 1 Port plate AISI 304 / PEEK x
92 1 Valve plate AISI 431 x
93 9 Back up ring PTFE x
94 9 O-ring Ø13 x 2 NBR x
121 1 Port ange AISI 316
122 1 O-ring Ø102 x 3 NBR x
123 1 O-ring Ø59,5 x 3 NBR x
124 1 Shaft sealing AISI 304 / NBR x
125 1 End cover AISI 316
126 1 Pin Ø5 x 10 AISI 304 x
127 6 Screw M8 x 60 AISI 304 x
128 4 Screw M8 x 50 AISI 304 x
1 Service instruction x x x x x x x
180B4333 - Seal set
(PAHT G 20-32)
180B4335 - Cylinder barrel set
(PAHT G 20-32)
180B4337 - Valve plate set
(PAHT G 20-32)
180B4336 - Piston set
(PAHT G 20-32)
180B4323 - Swash plate set
(PAHT G 20)
180B4324 - Swash plate set
(PAHT G 25)
180B4325 - Swash plate set
(PAHT G 32)
22
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
Page 23
Service guide | Disassembling and assembling PAHT / PAHT G 20-32
7. Exploded view
PAHT G 20-32
180R9175| 521B1108 | DKCFN.PI.012.E5.02 | 08.2019
23
Page 24
8. Tool sets
Qnt. Designation
1 Shaft bush, topedo x
1 Press tool 1 x
1 Press tool 2 x
180Z0236 - Tool set
(PAH / PAHT / PAHT G 20-32)
Danfoss A/S
High Pressure Pumps
DK-6430 Nordborg
Denmark
© Danfoss | DCS (im) | 2019.08
180R9175 | 521B1108 | DKCFN.PI.012.E5.02 | 24
Loading...