Service guide
MAH motor
MAH 6.3 - 12.5
Disassembling and assembling
hpp.danfoss.com
Service guide | Disassembling and assembling MAH 6.3 - 12.5
Table of Contents Introduction .......................................................................................................................................... 2
1. Disassembling the motor ................................................................................................................. 3
2. Inspection .............................................................................................................................................. 7
3. Assembling the motor ........................................................................................................................ 8
4. Service kit for MAH 6.3 ..................................................................................................................... 13
4.1. Service kit for MAH 12.5 ................................................................................................................... 14
5. Exploeded view MAH 6.3 ................................................................................................................ 15
5.1. Exploded view 12.5 ........................................................................................................................... 16
Introduction
NOTE: If the motor is disassembled within the warranty period, the motor is no longer covered
by the warranty.
This document covers the instructions for
disassembling and assembling the motor
MAH 6.3 - 12.5
Tools needed for disassembling/assembling the MAH 6.3 - 12.5 motor
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180R9152 | AX357937856579en-000402 | 07.2021
Service guide | Disassembling and assembling MAH 6.3 - 12.5
1. Disassembling the
motor
cover.
2. Dismantle front cover using a vice.1. Remove parallel key and unscrew front
4. Remove the two small O-rings from
ange. Remove seal from front cover using
3. Remove shaft seal using two screwdrivers.
a screwdriver.
5. Unscrew the four screws for housing. 6. Remove housing.
180R9152 | AX357937856579en-000402 | 07.2021
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
7. Remove pistons and retaining plate from
cylinder barrel.
8. Remove retaining guide.
10. Remove cylinder barrel.9. Remove pins and springs.
12. Remove guide pin.11. Remove port plate from ange.
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180R9152 | AX357937856579en-000402 | 07.2021
Service guide | Disassembling and assembling MAH 6.3 - 12.5
14. Remove O-ring from port.13 Remove O-ring from ange..
15. Loosen thrust plate using a screwdriver.
Place screwdriver in slot of thrust plate.
17. Wash all parts and replace all seals
(inclusive shaft seal).
Inspect all parts carefully (see ”Inspection”)
and replace any worn parts.
If the motor has failed, the reason for the
failure must be found and xed before the
repaired motor is re-installed.
16. Remove swash plate from housing.
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
18. Parts
Flange
Pistons
Port plate
Retaining plate
O-rings
Pins
Thrust plate with sealing
Swash plate Housing
Cylinder barrel
Retaining
guide
Front cover
Pins and springs
Seal
Screws and washers Shaft seal Washer
Spring
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180R9152 | AX357937856579en-000402 | 07.2021
Service guide | Disassembling and assembling MAH 6.3 - 12.5
2. Inspection 2.1. Port plate and thrust plate
1. Neither port plate nor thrust plate must
show any sign of wear.
2.2. Pistons
2. Hold a ruler against the surface of the
plates and check the tightness against a
light source.
1. The thickness of the piston shoes must be
at least 3.4 mm.
The play in the ball and socket joint must
not exceed 0.1 mm.
2.3 Cylinder barrel
1. Check outer bearing sur face for large wear
grooves (not critical).
Check that bushings are free from seizure
and large scratches.
Ensure that pistons can move freely in
bushings.
2. Hold a ruler against the surfaces of the
piston shoes to check that the surfaces
are even and smooth and without any
scratches.
2.4 Housing
1. Check that swash plate surface is smooth
and without any big scratches (depth
more than 0.1 mm).
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
3. Assembling
WARNING:
Do not use silicone when assembling the
motor. Do not reuse disassembled O-rings;
they might be damaged. Always use new
O-rings.
1. Mount O-ring on ange.
Important:
It is essential that the motoris serviced in
conditions of absolute cleanliness. All parts
must be absolute clean before mounting.
2. Mount guide pin.
3. Mount the O-ring in port.
Guide pin
4. Mount port pl ate in its right position using
pin as guide.
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
1.5 - 2.5 mm
5. Mount thrust plate with seals on cylinder
barrel.
6. Check that the gap between the cylinder
barrel and the thrust plate is 1.5-2.5 mm.
7. Mount the cylinder barrel in the ange. 8. Assemble pins and springs.
9. Mount pin/spring assemblies. 10. Mount the retainer guide.
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
11. Mount the retaining plate on the retainer
guide with plain surface pointing upwards.
13. Mount swash plate.
12. Insert the pistons.
14. Mount housing using pin as guide.
16. Mount the two O-rings in the ange.15. Tighten screws to a torque of 13 Nm.
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
upwards.
18. Mount spring.17. Mount washer with edge pointing
19. Fit hollow bush onto shaft. 20. Wet shaft seal and mount/slide it over
bush.
21. Use shaft seal tool when pressing shaft
22. Press shaft seal in position.
seal downwards.
180R9152 | AX357937856579en-000402 | 07.2021
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
23. Mount O-ring on front cover.
25. Press shaft seal into front cover using
shaft seal tool. Ensure that it is pressed to
the bottom.
24. Wet shaft seal with water and mount it in
front cover. .
26. Mount front cover and align it to screw
holes.
27. Tighten screws to a torque of 7 Nm. 28. Motor assembled.
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180R9152 | AX357937856579en-000402 | 07.2021
Service guide | Disassembling and assembling MAH 6.3 - 12.5
4. Service kit list for MAH 6.3
Pos. Qnt. Unit Designation Material
- 1 Pc. Shaft bush, torpedo -
- 1 Pc. Press tool for 18 mm shaft -
- 1 Pc. Mounting screw -
1 1 Pc. Housing with bearing (welded) AISI317Mg/PEEK
5 4 Pcs. Screw (M6 x 22 mm) A4
15 4 Pcs. Washer Stainless steel (1.4571)
16 1 Pc. Plug (G1/8") PA
17 1 Pc. Back-up ring PTFE
18 1 Pc. O-ring NBR
19 1 Pc. Sliding shoe PEEK
20 2 Pcs. Pin (∅4.0 x 8.0) A4
21 1 Pc. Swash plate Stainless steel (1.4057)
61 1 Pc. Cylinder barrel (assembled) ISO Stainless steel (1.4057)
62 5 Pcs. Preload spring (0.75 x 2.50 x 37 mm) Stainless steel (1.4310)
63 5 Pcs. Pin for retaining ball Stainless steel (1.4057)
64 1 Pc. Retaining ball Stainless steel (1.4057)
65 1 Pc. Int. retaining plate Stainless steel (1.4310)/PEEK
66 5 Pcs. Piston with piston shoes Stainless steel (1.4057)/PEEK
67 1 Pc. Key (5 x 5 x 20 mm) Stainless steel (1.4571)
91 1 Pc. Port plate Stainless steel (1.4301)/PEEK
92 1 Pc. Thrust plate Stainless steel (1.4301)/
(1.4057)
93 5 Pcs. Back-up ring PTFE
94 5 Pcs. O-ring (∅8.73 x ∅1.78) NBR
121 1 Pc. Port ange with bearing Stainless steel (1.4301)/PEEK
122 1 Pc. O-ring (∅65 x ∅3.00) NBR
123 1 Pc. O-ring (∅75.92 x ∅1.78) NBR
124 1 Pc. Shaft seal SIMRAX, AX15EA-018,
1.44301/C/AI203
125 1 Pc. Front cover Stainless steel (1.4301)
126 2 Pcs. Pin (∅4.0 x 8.0 mm) A4
127 2 Pcs Screw (M5 x 20 mm) A4
131 2 Pcs. Plug (G¼"; PA6.6; NV17 Ø20.5) PA
136 2 Pcs. O-ring (∅7.0 x ∅1.5) NBR
148 1 Pc. Dust seal (∅16.00 x 22.00 x 3.40 mm) N60 X
149 1 Pc. O-ring (∅24.0 x ∅2.0) NBR
150 1 Pc. Stainless steel
- 1 Service instruction (180R9151)
180F4002 - Shaft seal
X
X
X
X
X
X
X
X
X
X
X X X X X
180F4003 - Valve plate
(MAH 4-6.3 CW)
180F4004 - Piston kit
X
X
X
X
X
X
X
X X
X X
X X
X X
barrel
X
180F4005 - Cylinder
(MAH 4-6.3 CCW)
180F4006 - Valve plate
180Z0235 - Shaft seal
tool set
X
X
X
180R9152 | AX357937856579en-000402 | 07.2021
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Service guide | Disassembling and assembling MAH 6.3 - 12.5
4.1. Service kit list for MAH 12.5
Pos. Qnt. Unit Designation Material
- 1 Pc. Shaft bush, torpedo -
- 1 Pc. Press tool for 18 mm shaft -
- 1 Pc. Mounting screw -
1 1 Pc. Housing with bearing (welded) AISI317Mg/PEEK
5 4 Pcs. Screw (M8x25 mm) A4
15 4 Pcs. Washer Stainless steel (1.4571)
16 1 Pc. Plug (G1/8") PA
17 1 Pc. Back-up ring PTFE
18 1 Pc. O-ring NBR
19 1 Pc. Sliding shoe PEEK
20 2 Pcs. Pin (Ø4.0 x 8.0) A4
21 1 Pc. Swash plate Stainless steel (1.4057)
61 1 Pc. Cylinder barrel (assembled) ISO Stainless steel (1.4057)
62 5 Pcs. Preload spring (0.75 x 2.50 x 37 mm) Stainless steel (1.4310)
63 5 Pcs. Pin for retaining ball Stainless steel (1.4057)
64 1 Pc. Retaining ball Stainless steel (1.4057)
65 1 Pc. Int. retaining plate Stainless steel (1.4310)/PEEK
66 5 Pcs. Piston with piston shoes Stainless steel (1.4057)/PEEK
67 1 Pc. Key (5 x 5 x 20 mm) Stainless steel (1.4571)
91 1 Pc. Port plate Stainless steel (1.4301)/PEEK
92 1 Pc. Thrust plate Stainless steel (1.4301)/
(1.4057)
93 5 Pcs. Back-up ring PTFE
94 5 Pcs. O-ring (Ø8.73 xØ1.78) NBR
121 1 Pc. Port ange with bearing Stainless steel (1.4301)/PEEK
180F4012 - Shaft seal
X
X
X
180F4013 - Valve plate
(MAH 10-12.5 CW)
X X
X X
X X
X X
180F4014 - Piston kit
X
X
X
X
X
X
X
barrel
X
180F4015 - Cylinder
180F4016 - Valve plate
(MAH 10-12.5 CCW)
180Z0235 - Shaft seal
tool set
X
X
X
122 1 Pc. O-ring (Ø78 x Ø3.00) NBR
123 1 Pc. O-ring (Ø75.92 x Ø1.78) NBR
124 1 Pc. Shaft seal SIMRAX, AX15EA-018,
1.44301/C/AI203
125 1 Pc. Front cover Stainless steel (1.4301)
126 2 Pcs. Pin (Ø4.0 x 8.0 mm) A4
127 2 Pcs Screw (M5 x 20 mm) A4
131 2 Pcs. Plug (G¼"; PA6.6; NV17 Ø20.5) PA
136 2 Pcs. O-ring (Ø7.0 x Ø1.5) NBR
148 1 Pc. Dust seal (Ø16.00 x 22.00 x 3.40 mm) N60 X
149 1 Pc. O-ring (Ø29.0 xØ2.0) NBR
150 1 Pc. Stainless steel
- 1 Service instruction (180R9152)
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X
X
X
X
X
X
X
X X X X X
Service guide | Disassembling and assembling MAH 6.3 - 12.5
5. Exploded view
MAH 6.3
180R9152 | AX357937856579en-000402 | 07.2021
15
5.1. Exploded view
MAH 12.5
Danfoss A/S
High Pressure Pumps
Nordborgvej 81
DK-6430 Nordborg
Denmark
© Danfoss | DHS (im) | 2021.07
180R9152 | AX357937856579en-000402 | 16
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