Danfoss PAHT Series User manual

Service guide
PAHT / PAHT G pumps
PAHT 20-32 / PAHT G 20-32Product type -
Disassembling and assembling
hpp.danfoss.com

Service guide Disassembling and assembling PAHT / PAHT G 20-32
2
180R9175 / 521B1108 / DKCFN.PI.012.E3..02 / 01.2016
NOTE: If the pump is disassembled within the warranty period, the pump is no longer covered
by the warranty.
Introduction
Table of Contents
Contents
Introduction ............................................................................2
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
6. Spare parts list for PAHT G 20-32........................................................21
8. Tool sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
This document covers the instructions for disassembling and assembling the axial piston pumps
PAHT / PAHT G 20-32.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
3
180R9175 / 521B1108 / DKCFN.PI.012.E3.02 / 01.2016
1. Disassembling the
pump
2. Loosen and remove 6 screws.1. Tools required for dismantling the pump.
3. Remove mounting flange.
4. Remove shaft sealing.
Caution: Avoid scratching the sealing
surface on the shaft.
5. Remove spring. 6. Remove 2 guide pins.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
4
180R9175 / 521B1108 / DKCFN.PI.012.E3..02 / 01.2016
7. Remove O-ring. 8. Turn pump upside down.
11. View to pistons and retainer plate.
9. Loosen and remove 10 screws. 10. Remove cover.
12. Remove pistons and retainer plate.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
5
180R9175 / 521B1108 / DKCFN.PI.012.E3.02 / 01.2016
13. Remove retainer ball. 14. Remove retainer.
15. Remove spring. 16. Remove cylinder barrel.
18. Remove 1 guide pin.17.Remove port plate.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
6
180R9175 / 521B1108 / DKCFN.PI.012.E3..02 / 01.2016
19. Turn pump upside down. Loosen and
remove 4 screws. 20. Remove port flange.
21. Remove 1 guide pin.
23. Loosen thrust plate from cylinder barrel.
22. Remove O-ring from port flange.
24. Remove thrust plate.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
7
180R9175 / 521B1108 / DKCFN.PI.012.E3.02 / 01.2016
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.
30. Remove 2 guide pins from end cover
plate.29. Remove swash plate.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
8
180R9175 / 521B1108 / DKCFN.PI.012.E3..02 / 01.2016
31. Remove O-ring from end cover plate.
32. Remove shaft sealing from mounting
flange.
33.
34. Pump
disassembled.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
9
180R9175 / 521B1108 / DKCFN.PI.012.E3.02 / 01.2016
1. Neither valve plate nor thrust plate must
show any sign of wear. .
1. Check that surface of swash plate is
smooth and without any large scratches
(depth more than 0.1 mm)..
2. Hold a ruler against surface of plate and
check tightness against a light source..
2. Inspection
2.2. Swash plate:
2.1. Valve and thrust plate:
3. Check that both O-rings and back-up rings
are not broken and do not show severe
wear.

Service guide Disassembling and assembling PAHT / PAHT G 20-32
10
180R9175 / 521B1108 / DKCFN.PI.012.E3..02 / 01.2016
5. Check main bearing for wear and
scratches.
4. Check bushes in cylinderbarrel for wear
and scratches.
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.
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..
2.3. Pistons: