Danfoss APP 21, APP 46 Service guide

Service guide

APP pumps

APP 21 - 46 and APP W HC 15 - 30 Disassembling and assembling

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

Table of Contents

1. Introduction

Contents

1. Introduction .............................................................................................................................................................. 2

2. Disassembling the pump ..................................................................................................................................... 3

3. Assembling the pump .......................................................................................................................................... 6

4. Disassembling and assembling of the swash plate ..................................................................................10

5. Disassembling andassembling of cylinder barrel and valve plate ......................................................11

6. Disassembling and assembling of the ﬂush valve ....................................................................................11

7. Changing pistons ..................................................................................................................................................12

8. When should the pistons be replaced ...........................................................................................................17

9. Exploded view APP 21-26 , APP 30/1500 and APP W HC 15-24 ..........................................................18

10. Exploded view APP 30/1200, APP 38/1500, APP 46/1780 and APP W HC 30 ..................................19

This document covers the instructions for disassembling and assembling the axial piston pumps APP 21-46 and APP W HC 15-30

Tools provided with toolset 180B4172:

• 10 mm combination wrench

• 13 mm combination wrench

• 6 mm allen key

• Adjustable pin wrench

• Stop for retainer plate

• Press bush for valve plate

• Shaft seal extractor ø45

• M8 allen screw (20 mm and 140 mm)

• Press bush ø45 (Plastic)

• M8 mm eye bolt

• M8 mm nut

• M8 x 70 mm screw

Important: It is essential that the pump is serviced in conditions of absolute cleanliness.

Place the pump on a pallet or other stable surface above the ground. Ensure that the pump cannot roll. It must be possible to place the pump vertically with the shaft pointing downwards. This can be done between two pallets or between two boards on a pallet provided that the distance is minimum 50 mm.

For a better understanding of the pump, please see the exploded view on page 18 and 19.

WARNING: Do not reuse disassembled O-rings or shaft seal as they might be damaged. Always use new O-rings.

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

2. Disassembling the pump

1. Disconnect the pump and motor from the system. Remove non-return valve and connector from the pump.

2. Using a 10 mm combination wrench, unscrew the four bolts from shaft seal ﬂange. If shaft seal ﬂange is stuck, screw in two bolts in holes in the ﬂange to remove it.

3. Remove ceramic ring from ﬂange by gently pushing it from the back of the sealing ring.

6. Carefully remove the shaft seal assembly using the shaft seal extractor supplied in the toolset. The extractor must ﬁt underneath the shaft seal. Press the arms of the extractor together when turning the bolt.

4. Mount the M8 allen screw from the tool set in the top of the shaft.

5. Wet the shaft and shaft seal with clean ﬁltered water.

7. Turn pump into vertical position with shaft pointing downwards.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

8. Using a 13 mm combination wrench, remove all the bolts on the mounting ﬂange except the three shown in the next picture.

WARNING:

Do not loosen the two screws keeping swash plate in place.

9. Unscrew the remaining three bolts. Turn

each bolt one round at the time to make sure that the ﬂange is removed as straight forward as possible.

10. Screw the eye bolt in the M8 hole in the middle of the ﬂange. Pull it straight upwards.

12. Remove by hand the pistons one by one. Be careful not to scratch the pistons. Tilt the retainer plate to horizontal position for easy removal of pistons, if required.

WARNING:

Do not use any tools.

11. Swash plate must be placed so that its

surface is not scratched. For further disassembling of swash plate, see page 10.

13. Remove the retainer plate and the retainer

ball. Warning: So not loosen the three screws

in the retainer plate.

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

14. Remove the retainer guide, the 4 springs and the spring guide.

15. Mount a 8 mm eye bolt in the cylinder

barrel. Pull straight upwards. A continuous lift will elevate the cylinder barrel out of housing. This can only be done if shaft seal is removed.

WARNING:

If the cylinder barrel is dropped or lowered too fast into housing, the main bearing/shaft bearing might be damaged. It is not replaceable.

16. Place cylinder barrel upside down. For further disassembling of cylinder barrel and valve plate see page 11.

18. Remove, by hand, the two pins. Note: The following operation is only

necessary if O-ring on port ﬂange is to be changed.

17. Remove the port plate by hand.

19. Place the pump horizontally.

20. Remove the remaining screws in port

ﬂange by using a 13 mm combination wrench. Carefully separate house and port ﬂange. Ensure that pin for the positioning house is not lost.

21. For further disassembling of ﬂush valve,

see page 11.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

3. Assembling the pump WARNING:

Do not use silicone when assembling the pump. Do not reuse disassembled O-rings; they might be damaged. Always use new O-rings.

Note: Place the pump on a pallet or other stable surface above the ground. Ensure that the pump cannot roll. It must be possible to place the pump vertically with the shaft pointing downwards. This can be done between two pallets or between two boards on a pallet provided that the distance is minimum 50 mm.

Important: It is essential that the pump is serviced in conditions of absolute cleanliness. All parts must be absolute clean before mounting.

1. Lubrication:

• To prevent seizing-up, lubricate all threads with PTFE lubrication type.

• O-rings inside pump may be lubricated only with clean ﬁltered water.

• O-rings for port ﬂange, mounting ﬂange and ﬂushing valve must be lubricated.

• It is important to lubricate ALL parts to be assembled with clean ﬁltered water (Especially all PEEK parts).

3. Mount O-ring.

4. Insert pin for positioning housing

on port ﬂange. Ensure that two screw holes can be reached from below.

2. Place port ﬂange with O-ring pointing upwards.

5. Position housing aligning pin hole over guide pin.

6. Gently press downwards. Be careful not to squeeze O-ring. If O-ring is damaged, the pump will leak.

7. Screw in at least two screws.

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

8. Place housing horizontally. Screw in the

rest of the screws on port ﬂange. Tighten screws to a torque according to exploded view.

11. Ensure port plate is ﬁtted tightly against

the bottom. IMPORTANT:

Lubricate port plate with clean ﬁltered fresh water. If valve plate is disassembled from cylinder barrel please see page 11 before continuing.

9. Place pump vertically. Place 10.5 mm pins in port ﬂange.

10. Position port plate by using the two pins. Do not use force for this operation.

12. Screw eye bolt in cylinder barrel.

13. Make sure there is enough free space for the shaft beneath the housing. Gently lower cylinder barrel into housing.

WARNING!

If cylinder barrel is dropped or lowered too fast into housing, main bearing and shaft bearing might be damaged. Replacement can only be done at Danfoss, Nordborg.

14. Unscrew M8 eye bolt.

15. Place the four springs and spring guide in

cylinder barrel. Springs must be positioned in the holes.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

16. Retainer guide, retainer ball and

retainer plate must be mounted as indicated in below picture.

17. Place retainer plate in cylinder barrel. Note: If pistons are replaced, place new

pistons in clean ﬁltered water for a couple of minutes. Exercise piston shoes to make them “run” smoother.

19. Place pistons in retainer plate and cylinder barrel. When pistons are placed, tilt retainer plate for easier placement of swash plate. If swash plate has been disassembled from mounting ﬂange, see page 10 for assembly of swash plate.

20. Lubricate piston shoes and swash plate with clean ﬁltered water. Remember to place the pins in housing.

21. Place the pins in the housing.

22. Place the mounting ﬂange. Remember to place the guide pin in the housing. . Place three bolts in mounting ﬂange. Turn each bolt one round at a time to ensure mounting ﬂange is mounted as straight downwards as possible. Be careful not to squeeze O-ring.

23. Screw in the rest of the bolts and cross tighten all screws to a torque according to exploded view.

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24. Place pump horizontally to get access to shaft.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

25. Lubricate shaft with clean ﬁltered water.

26. Place stop for shaft seal on shaft.

WARNING: Ensure that carbon ring is pointing

outwards.

27. Use plastic assembly tool provided with large diameter pointing downwards, to press seal home against shoulder of stop for shaft seal.

28. Press new ceramic ring into retainer ring by using plastic tool provided.

WARNING: Ensure that the face with rubber seal is positioned against shoulder in shaft seal ﬂange.

30. Place shaft seal ﬂange on shaft. Tighten

the bolts with a torque according to exploded view.

29. Remove old O-ring and ﬁt new one on shaft seal ﬂange.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

4. Disassembling and assembling of the swash plate

WARNING: Make sure that the surface on the swash plate does not get any marks.

1. Place the swash plate upside down.

Remove the 2 bolts holding the swash plate. Remove the mounting ﬂange from the swash plate.

2. Check that the O-ring and pin are in good condition (provided with seal set).

3. Change the O-ring on the mounting

ﬂange.

4. Mount the swash plate on the 2 pins. Carefully by hand tilt the unit to horizontal position and mount the 2 bolts which hold the swash plate. Tighten the bolts with a torqueaccording to exploded view. Finally check the surface on the swash plate for any marks or foreign particles.

5. Mount the assembled part on the pump.

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

5. Disassembling and assembling of cylinder barrel and valve plate

1. Push a screwdriver into the hole between

cylinder barrel and valve plate. Carefully push downward the screwdriver so that it makes a gap between cylinder barrel and valve plate. Use this gap to put in another screwdriver and loosen the valve plate from the cylinder barrel.

Mount

backup

rings ﬁrst

Mount then

O-rings

2. Remove the O-rings and backup rings. If they have been removed they can not be reused. Mount the new back-up rings on the valve plate ﬁrst and then mount the O-rings.

6. Disassembling and assembling of the ﬂush valve

3. Lubricate the new O-rings/back-up rings

and the liners in the cylinder barrel with clean ﬁltered water. Lower the valve plate upside down on the cylinder barrel. Place the press bush for valve plate (provided in tool set) like on the picture. Screw the bolt into the shaft of the cylinder barrel. Turn the nut slowly clockwise. The valve plate must slide carefully into the cylinder barrel. Stop when the gap between cylinder barrel and valve plate is 1-2 mm.

1. Unscrew the ﬂush valve counter-clockwise

by using a pin wrench.

4. Remove the press bush again by screwing the nut counter-clockwise.

Turn the nut slowly clockwise. The valve plate must slide gently into the cylinder barrel. Stop when the gap between cylinder barrel and valve plate is 1–2 mm.

2. Remove the O-rings (green and black). If necessary, change the valve cone, spring and plug. If the spring is changed it is important that it is located like on the picture. The end of the spring must be against the shoulder of the valve cone.

3. Put a little amount of grease on the thread on the plug. Screw it into the port ﬂange. Tighten with a torque according to exploded view.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

7. Changing pistons

Tools needed are:

• 13 mm combination wrench

• 6 mm allen key:

•

• Service kit - see parts list 521B0941

7.1 Disassembling

1. Disconnect the pump from the rest of the system. Warning:

Never unscrew the 4 screws marked with coloured sealer.

3. Mount the guide bolt in the top hole. 4. Unscrew the remaining three screws

2. Loosen all screws on the pump except the three screws as shown above. Note:

There is still water inside the pump.

by using the combination wrench to turn each screw a couple of rounds at a time so the ﬂange is removed as straight forward as possible..

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

Drain plug

5. If the ﬂange does not move forward - loosen the drain plug to empty the pump from water by releasing vacuum.

Swash plate surface

7. Carefully turn the ﬂange and push it backwards to make it rest on the housing surface. Ensure not to scratch the swash plate surface.

6. Remove the ﬂange when the remaining three screws have been loosened. The guide bolt must remain mounted.

8. Adjust the retainer plate to be parrallel to the end ﬂange.

9. Screw the stop for the retainer plate into

the centre to keep retainer plate/retainer ball assembly in place.

10. Carefully remove the pistons one by one.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

11. Warning: Ensure that the piston shoes and the piston surfaces are not damaged during removal. It is recommended to place the pistons upside down on an even and clean base/surface.

12. Inspect the piston liners.

Replace any worn parts.

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

7.2 Assembling

1. Lubricate pistons with clean ﬁltered water.

Insert the pistons arbitrarily.

4. Place the retainer plate in an angle

corresponding to the orientation of the swash plate.

2. Remove the stop for retainer plate.

5. Tilt the ﬂange and replace the ﬂange O-ring.

6. Turn the ﬂange and gently push it into the

housing.

7. Mount the three screws as shown above. Tighten them to a torque according to exploded view.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

8. Remove the guide bolt.

Mount the remaining screws and cross tighten them to a torque according to exploded view.

9. Connect the pump to the rest of the system and bleed the pump.

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

8. When should the pistons be replaced

This section provides guidance on, how to determine whether the parts of APP 21-43 are worn and should be replaced. In case of doubt - the pistons must be replaced. The pictures below are ment as a guideline for evaluating the wear of the sliding surface.

1. No wear or cavitation of the piston shoe. New inspection is required in 4,000 hours.

Note: If the pistons break down, the pump will suﬀer a disastrous breakdown.

2. Cavitation of the piston shoes. New inspection is required in 2,000 hours.

3. Cavitation of the piston shoes.

All pistons must be replaced within the next 1,000 hours.

Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 -30

9. Exploded view APP 21-26 , APP 30/1500 and

APP W HC 15-24

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Service guide | Disassembling and Assembling, APP 21 - 46 and APP W HC 15 - 30

10. Exploded view APP 30/1200, APP 38/1500, APP 46/1780 and APP W HC 30

Danfoss A/S High Pressure Pumps DK-6430 Nordborg Denmark

180R9406 | AX274339308034en-000301 | 20

Danfoss APP 21, APP 46 Service guide

Specifications and Main Features

Frequently Asked Questions

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