Danfoss APP S 21-38, APP S 674 21-38 Service guide
Service guide
APP S / APP S 674 pumps
APP S 21-38 / APP S 674 21-38
Disassembling and assembling
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Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
Table of Contents |
1. |
Disassembling . . . . . |
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2. |
Disassembling the pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 |
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3. |
Assembling the pump . |
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4. |
Disassembling and assembling of the swash plate . . . . . . . . . |
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14 |
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5. |
Disassembling and assembling of cylinder barrel-/ valve plate . . . |
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15 |
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6. Disassembling and assembling of the flush valve . . . . . . . . . . . . . . . . . . . .16
7. Changing pistons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1.Disassembling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
7.2. Assembling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
8. Exploded view APP S (674) 21-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
9.When should the pistons be replaced . . . . . . . . . . . . . . . . . . . . . . . . . 23
This document covers the instructions for disassembling and assembling the axial piston pumps APP S (674) 21-38.
Tools provided with toolset 180B4347: |
• Press bush ø 45 (Plastic) |
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Adjustable pin wrench |
• M8 mm eye bolt |
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• Stop for retainer plate |
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M8 mm nut |
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• Press bush for valve plate |
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M8 x 70 mm screw |
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M8 allen screw (20 mm and 140 mm) |
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1. Disassembling |
Important: It is essential that the pump is |
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serviced in conditions of absolute cleanliness. |
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Place the pump on a pallet or other stable |
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surface above the ground. Ensure that the pump |
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cannot roll. It must be possible to place the |
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pump vertically with the shaft pointing down- |
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wards. This can be done between two pallets or |
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between two boards on a pallet provided that |
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the distance is minimum 50 mm. |
For a better understanding of the pump, please see the exploded view in item 8.
WARNING:
Do not reuse disassembled O-rings or shaft seal as they might be damaged. Always use new O-rings.
2 |
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
2. Disassembling the |
1. Disconnect the pump from the rest of the |
pump |
system. |
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3.Carefully remove the stop bush ring and the O-ring with a screw driver.
5.Place two bolts in screw holes in the flange.
2.Lubricate shaft with clean filtered water.
4.Using a 10 mm combination wrench, unscrew the four bolts from shaft seal flange.
WARNING!
Place the shaft seal press bush tool to ensure the flange does not pop out and damage the ceramic ring.
6.Remove flange slowly.
WARNING!
Be careful, the shaft has sharp edges.
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
3 |
Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
7.Remove O-ring. Remove ceramic ring from flange by carefully pushing it from the back of the sealing ring.
9.Place the press bush tool over the shaft seal again. Through the inlet port lift the shaft seal with a screwdriver between shaft seal and spring.
WARNING!
Be careful not to scratch the shaft.
11.Carefully remove the spring by lifting it with a screwdriver.
8.Wet the shaft and shaft seal with clean filtered water.
10. Carefully remove the shaft seal and ring.
12.Turn pump into vertical position with shaft pointing downwards and remove the shaft seal distance ring.
4 |
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
13.Using the 13 mm combination wrench, remove all the bolts on the mounting flange except the three shown in the picture under item 14.
WARNING:
Do not loosen the two screws keeping swash plate in place.
15.Screw the eye bolt in the M8 hole in the middle of the flange. Pull it straight upwards.
14.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.
16.Swash plate must be placed so that its surface is not scratched. For further disassembling of swash plate, see page 14.
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
5 |
Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
17.Remove by hand the pistons one by one. Be careful not to scratch the pistons.
If required, tilt the retainer plate to horizontal position for easy removal of pistons.
WARNING:
Do not use any tools.
19.Remove the retaining guide, the 4 springs and the spring guide.
18.Remove the retaining plate and the retaining ball.
Note: As the retaining ball is not attached to the retaining plate, it might fall out.
20.Mount the 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.
6 |
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
21.Place cylinder barrel upside down. For further disassembling of cylinder barrel and valve plate see page 15.
23.Remove, by hand, the two guide pins.
Note: The following operation is only necessary if O-ring on port flange is to be changed.
25.Remove the remaining screws in port flange by using a 13 mm combination wrench.
22. Remove the port plate by hand.
24. Place the pump horizontally.
26.Carefully separate house and port flange. Ensure that guide pin for the positioning house is not lost. For further disassembling of flush valve, see page 16.
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
7 |
Service guide | Disassembling and assembling APP S 21-38 / APP S 674 21-38
3.Assembling the pump
WARNING: |
Important: |
Do not use silicone when assembling the |
It is essential that the pump is serviced in |
pump. Do not reuse disassembled O-rings; |
conditions of absolute cleanliness. All parts |
they might be damaged. Always use new |
must be absolute clean before mounting. |
O-rings. |
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1.Lubrication:
•To prevent seizing-up, lubricate all threads with PTFE lubrication type.
•O-rings inside pump must 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).
2.Place port flange with O-ring pointing upwards.
3.Insert guide pin for positioning housing on port flange.
Ensure that two screw holes can be reached from below.
4.Mount O-ring.
5.Position housing aligning pin hole over guide pin.
6.Carefully 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.
8 |
180R9278 | 521B1306 | DKCFN.PI.013.D3.02 | 05.2016 |
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