Danfoss APP series User manual

Service guide
APP pumps
APP(W) 5.1-10.2
Disassembling and assembling
hpp.danfoss.com

Service guide |Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.062 | 180R9238 | DKCFN.PI.078.F3.02 | 521B1196
Table of Contents
NOTE: If the pump is disassembled within the warranty period, the pump is no longer covered
by the warranty.
Introduction
This document covers the instructions for
disassembling and assembling the axial piston
pump APP(W) 5.1-10.2
Tools needed:
• Toolset (code no. 180B4162)
• Seal set (code no. 180B4161)
• Screwdriver
Important: It is essential that the pump is
serviced in conditions of absolute cleanliness.
To understand the pump design better, please
see exploded view on last page.
WARNING: Do not reuse disassembled O-ring
or shaft seal as they might be damaged.
Contents
Introduction ................................................................................................................................................................................2
1. Disassembling the pump..............................................................................................................................................3
2. Assembling the pump ...................................................................................................................................................5
3. Disassembling swash plate..........................................................................................................................................6
4. Assembling swash plate................................................................................................................................................7
5. Change of shaft seal .......................................................................................................................................................8
6. Exploded view for APP (W) 5.1-10.2 ...................................................................................................................... 12

Service guide | Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.06 180R9238 | DKCFN.PI.078.F3.02 | 521B1196 | 3
1. Disassembling the pump
2. Unscrew the 8 screws in the mounting
flange.
5. Carefully remove the shaft seal assembly
using the shaft-seal extractor supplied,
provided with the tool set. The extractor
must fit underneath the shaft seal.
7. Remove the pistons, retainer plate, stop
bush and retainer ball from the cylinder
barrel.
1. Unscrew the seal-retaining ring
counterclockwise and remove it.
4. Wet the shaft and shaft seal with clean
(filtered) water.
3. Carefully remove the mounting flange
from the housing.
6. Remove the whole cylinder barrel and
carefully place it on a suitable clean
surface.

Service guide | Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.06 180R9238 | DKCFN.PI.078.F3.02 | 521B1196 | 4
8. Carefully remove the valve plate assembly
using a screwdriver.
11. Mount the new O-rings.
13. Remove the port plate by hand.
10. Mount the new back-up rings on the new
valve plate.
9. Remove the O-rings and back-up rings
from the valve plate.
12. Carefully press, by hand, the cylinder
barrel onto the valve plate.
Mount backup
ring first
Then mount
O-ring

Service guide | Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.06 180R9238 | DKCFN.PI.078.F3.02 | 521B1196 | 5
Important: It is essential that the pump is
serviced in conditions of absolute cleanliness. WARNING: Do not reuse disassembled O-ring or shaft seal as they might be damaged.
2. Assembling the pump
5. Position all the pistons, one in each piston
bore, in the cylinder barrel. It may be
necessary to tilt the retaining ring to allow
the pistons to fit into the piston bores.
4. Carefully position all the pistons into the
retainer plate.
3. Fit the retainer guide onto the shoulder of
the shaft.
7. Mount the new shaft seal following the
instructions in chapter 5 see page 8-11.
6. Position the new white stop bush on top
of the retainer guide.
2. Carefully slide the cylinder barrel into the
housing.
1. When mounting the port plate position
the port plate over the guide pin.
IMPORTANT: Make sure that the guide pin
is located in the locating hole in the port
plate.
Guide pin

Service guide | Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.06 180R9238 | DKCFN.PI.078.F3.02 | 521B1196 | 6
11. Mount the seal retainer ring Tighten the
ring with a torque of 60 ± 5 Nm.
Turn each screw 2 rounds at a time to
ensure the flange is mounted as straight as
possible Tighten the screws to a torque of
30 ±3 Nm.
To prevent seizing-up, lubricate
the threads on the 8 screws with grease,
screw them into the pump and tighten by
hand. Use Molykote® D paste from Dow
Corning or Klüber UH1 84-201 from Klüber
lubrication.
10. Screw the 8 screws into the flange and the
housing.
8. Position the guide pin in the housing.
9. Position and carefully press, by hand, the
combined flange and swash plate into the
housing.
IMPORTANT: Ensure not to cut the O-ring.
2. Turn the mounting flange upside down.1. Unscrew the screw in the mounting flange.
3. Disassembling swash
plate
Guide pin

Service guide | Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.06 180R9238 | DKCFN.PI.078.F3.02 | 521B1196 | 7
2. Mount the spacer on the swash plate.1. Replace the O-rings.
3. Remove the swash plate and the spacer.
3. Position the swash plate on the mounting
flange using the guide pins and fix it with
the screw.
4. The mounting flange is now ready to be
mounted on the housing.
4. Assembling swash plate

Service guide |Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.068 | 180R9238 | DKCFN.PI.078.F3.02 | 521B1196
5. Change of shaft seal
1. Unscrew the seal retaining ring
counterclockwise and remove it.Tools provided according to 180B4162
3. Carefully remove the flange from the
casing.
4. Wet the shaft and shaft seal with clean
filtered water.
2. Unscrew the 8 screws in the mounting
flange.
5. Carefully remove the shaft seal assembly
using the shaft-seal extractor supplied.
The extractor must fit underneath the
shaft seal.

Service guide | Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.06 180R9238 | DKCFN.PI.078.F3.02 | 521B1196 | 9
7. Scrap the old stop bush (if black) and
place the new white stop bush on top of
the retaining guide.
10. Slide the new shaft seal over the torpedo
with the carbon seal face pointing
upwards (see also drawing on last page).
IMPORTANT: Be careful not to damage
the carbon seal face on the shaft seal.
6. Ensure that no dirt has entered into the
pump.
IMPORTANT: If loose particles are
observed, the pump must be
dismantled and thoroughly cleaned
with clean filtered water.
8. Fit the hollow bush (torpedo) onto the
shaft.
9. Thoroughly wet the torpedo, shaft and
replacement shaft seal with plenty of clean
filtered water. Do not use silicone grease.
11. Use the plastic assembly tool provided,
large diameter pointing downwards, to
press the seal home against the shoulder
of the spacer.

Service guide |Disassembling and Assembling, APP(W) 5.1-10.2
© Danfoss | DCS (im) | 2017.0610 | 180R9238 | DKCFN.PI.078.F3.02 | 521B1196
12. Remove the old O-ring and fit the
new O-ring on the adapter.
14. Screw the 8 screws into the flange and
the casing. To prevent cold welding,
lubricate the threads on the 8 screws
with grease, screw them into the pump
and tighten by hand. Use Molykote® D
paste from Dow Corning or Klüber UH1
84-201 from Klüber lubrication.
13. Place the guide pin in the casing. Position
the combined flange and swash plate onto
the guide pin and press it gently, by hand,
into the casing.
Ensure not to squeeze the O-ring.
15. Remove the ceramic ring from the seal
retaining ring.
16. Wet the parts with clean filtered water.
Guide pin