Danfoss APP 21-43, APP 43/1, 700, APP 21-26, APP 30/1 Service Manual

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Service guide

APP pumps

APP 21-43 Disassembling and assembling

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Service guide | Disassembling and Assembling, APP 21-43

Table of Contents 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 and assembling of cylinder barrel and valve plate .....................................................11

6. Disassembling and assembling of the ush valve ....................................................................................11

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

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

9. Exploded view APP 21-26 and APP 30/1,500 ..............................................................................................18

10. Exploded view APP 30/1,200, APP 38/1,500, APP 43/1,700 ...................................................................19

1. Introduction

This document covers the instructions for disassembling and assembling the axial piston pumps APP 21-43.

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 12 and 13.

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

Service guide | Disassembling and Assembling, APP 21-43

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 ange. If shaft seal ange is stuck, screw in two bolts in holes in the ange to remove it.

3. Remove ceramic ring from ange 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 t 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 ltered water.

7. Turn pump into vertical position with shaft

pointing downwards.

Service guide | Disassembling and Assembling, APP 21-43

8. Using a 13 mm combination wrench, remove all the bolts on the mounting ange 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 ange is removed as straight forward as possible.

10. Screw the eye bolt in the M8 hole in the middle of the ange. 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. Note: As the retainer ball is not attached

to the retainer plate, it might fall out.

Service guide | Disassembling and Assembling, APP 21-43

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 ange is to be changed.

17. Remove the port plate by hand.

19. Place the pump horizontally.

20. Remove the remaining screws in port

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

21. For further disassembling of ush valve,

see page 11.

Service guide | Disassembling and Assembling, APP 21-43

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 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).

3. Mount O-ring.

4. Insert pin for positioning housing

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

2. Place port ange with O-ring pointing upwards.

5. Position housing alingning 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.

+ 14 hidden pages

Danfoss APP 21-43, APP 43/1, 700, APP 21-26, APP 30/1 Service Manual

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