Danfoss MAH Series User manual

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
2180R9152 | AX357937856579en-000402 | 07.2021
NOTE: If the motor is disassembled within the warranty period, the motor is no longer covered
by the warranty.
Introduction
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
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

Service guide | Disassembling and assembling MAH 6.3 - 12.5
3
180R9152 | AX357937856579en-000402 | 07.2021
1. Disassembling the
motor
2. Dismantle front cover using a vice.1. Remove parallel key and unscrew front
cover.
3. Remove shaft seal using two screwdrivers.
4. Remove the two small O-rings from
ange.Removesealfromfrontcoverusing
a screwdriver.
5. Unscrew the four screws for housing. 6. Remove housing.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
4180R9152 | AX357937856579en-000402 | 07.2021
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.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
5
180R9152 | AX357937856579en-000402 | 07.2021
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.
16. Remove swash plate from housing.
17. Wash all parts and replace all seals
(inclusive shaft seal).
Inspect allpartscarefully(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.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
6180R9152 | AX357937856579en-000402 | 07.2021
Thrust plate with sealing Swash plate Housing
Cylinder barrel
Retaining
guide
Front cover
Pins and springs
Seal
Flange
Pistons
Port plate
Retaining plate
O-rings
Pins
Screws and washers Shaft seal Washer Spring
18. Parts

Service guide | Disassembling and assembling MAH 6.3 - 12.5
7
180R9152 | AX357937856579en-000402 | 07.2021
2. Hold a ruler against the surface of the
plates and check the tightness against a
light source.
1. Neither port plate nor thrust plate must
show any sign of wear.
2. Inspection 2.1. Port plate and thrust plate
2. Hold a ruler against the surfaces of the
piston shoes to check that the surfaces
are even and smooth and without any
scratches.
2.2. Pistons
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 outerbearingsurfaceforlargewear
grooves (not critical).
Check that bushings are free from seizure
and large scratches.
Ensure that pistons can move freely in
bushings.
1. Check that swash plate surface is smooth
and without any big scratches (depth
more than 0.1 mm).
2.4 Housing

Service guide | Disassembling and assembling MAH 6.3 - 12.5
8180R9152 | AX357937856579en-000402 | 07.2021
1. Mount O-ring on ange. 2. Mount guide pin.
WARNING:
Do not use silicone when assembling the
motor. Do not reuse disassembled O-rings;
they might be damaged. Always use new
O-rings.
3. Assembling
Important:
It is essential that the motoris serviced in
conditions of absolute cleanliness. All parts
must be absolute clean before mounting.
4. Mountportplateinitsrightpositionusing
pin as guide.
3. Mount the O-ring in port.
Guide pin

Service guide | Disassembling and assembling MAH 6.3 - 12.5
9
180R9152 | AX357937856579en-000402 | 07.2021
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.
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.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
10 180R9152 | AX357937856579en-000402 | 07.2021
12. Insert the pistons.
11. Mount the retaining plate on the retainer
guide with plain surface pointing upwards.
14. Mount housing using pin as guide.
13. Mount swash plate.
16. Mount the two O-rings in the ange.15. Tighten screws to a torque of 13 Nm.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
11
180R9152 | AX357937856579en-000402 | 07.2021
18. Mount spring.17. Mount washer with edge pointing
upwards.
19. Fit hollow bush onto shaft. 20. Wet shaft seal and mount/slide it over
bush.
21. Use shaft seal tool when pressing shaft
seal downwards.
22. Press shaft seal in position.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
12 180R9152 | AX357937856579en-000402 | 07.2021
24. Wet shaft seal with water and mount it in
front cover. .
23. Mount O-ring on front cover.
26. Mount front cover and align it to screw
holes.
25. Press shaft seal into front cover using
shaft seal tool. Ensure that it is pressed to
the bottom.
27. Tighten screws to a torque of 7 Nm. 28. Motor assembled.

Service guide | Disassembling and assembling MAH 6.3 - 12.5
13
180R9152 | AX357937856579en-000402 | 07.2021
180F4002 - Shaft seal 180F4003 - Valve plate (MAH 4-6.3 CW) 180F4004 - Piston kit 180F4005 - Cylinder barrel 180F4006 - Valve plate (MAH 4-6.3 CCW) 180Z0235 - Shaft seal tool set
Pos. Qnt. Unit Designation Material
- 1 Pc. Shaft bush, torpedo - X
- 1 Pc. Press tool for 18 mm shaft - X
- 1 Pc. Mounting screw - X
1 1 Pc. Housing with bearing (welded) AISI317Mg/PEEK
5 4 Pcs. Screw (M6 x 22 mm) A4 X
15 4 Pcs. Washer Stainless steel (1.4571) X
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 X
21 1 Pc. Swash plate Stainless steel (1.4057) X
61 1 Pc. Cylinder barrel (assembled) ISO Stainless steel (1.4057) X
62 5 Pcs. Preload spring (0.75 x 2.50 x 37 mm) Stainless steel (1.4310) X
63 5 Pcs. Pin for retaining ball Stainless steel (1.4057) X
64 1 Pc. Retaining ball Stainless steel (1.4057) X
65 1 Pc. Int. retaining plate Stainless steel (1.4310)/PEEK X
66 5 Pcs. Piston with piston shoes Stainless steel (1.4057)/PEEK X
67 1 Pc. Key (5 x 5 x 20 mm) Stainless steel (1.4571) X
91 1 Pc. Port plate Stainless steel (1.4301)/PEEK X X
92 1 Pc. Thrust plate Stainless steel (1.4301)/
(1.4057) X X
93 5 Pcs. Back-up ring PTFE X X
94 5 Pcs. O-ring (∅8.73 x ∅1.78) NBR X X
121 1 Pc. Port ange with bearing Stainless steel (1.4301)/PEEK
122 1 Pc. O-ring (∅65 x ∅3.00) NBR X
123 1 Pc. O-ring (∅75.92 x ∅1.78) NBR X
124 1 Pc. Shaft seal SIMRAX, AX15EA-018,
1.44301/C/AI203 X
125 1 Pc. Front cover Stainless steel (1.4301)
126 2 Pcs. Pin (∅4.0 x 8.0 mm) A4 X
127 2 Pcs Screw (M5 x 20 mm) A4 X
131 2 Pcs. Plug (G¼"; PA6.6; NV17 Ø20.5) PA
136 2 Pcs. O-ring (∅7.0 x ∅1.5) NBR X
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 X
150 1 Pc. Stainless steel
- 1 Service instruction (180R9151) X X X X X
4. Service kit list for MAH 6.3

Service guide | Disassembling and assembling MAH 6.3 - 12.5
14 180R9152 | AX357937856579en-000402 | 07.2021
180F4012 - Shaft seal 180F4013 - Valve plate (MAH 10-12.5 CW) 180F4014 - Piston kit 180F4015 - Cylinder barrel 180F4016 - Valve plate (MAH 10-12.5 CCW) 180Z0235 - Shaft seal tool set
Pos. Qnt. Unit Designation Material
- 1 Pc. Shaft bush, torpedo - X
- 1 Pc. Press tool for 18 mm shaft - X
- 1 Pc. Mounting screw - X
1 1 Pc. Housing with bearing (welded) AISI317Mg/PEEK
5 4 Pcs. Screw (M8x25 mm) A4 X
15 4 Pcs. Washer Stainless steel (1.4571) X
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 X
21 1 Pc. Swash plate Stainless steel (1.4057) X
61 1 Pc. Cylinder barrel (assembled) ISO Stainless steel (1.4057) X
62 5 Pcs. Preload spring (0.75 x 2.50 x 37 mm) Stainless steel (1.4310) X
63 5 Pcs. Pin for retaining ball Stainless steel (1.4057) X
64 1 Pc. Retaining ball Stainless steel (1.4057) X
65 1 Pc. Int. retaining plate Stainless steel (1.4310)/PEEK X
66 5 Pcs. Piston with piston shoes Stainless steel (1.4057)/PEEK X
67 1 Pc. Key (5 x 5 x 20 mm) Stainless steel (1.4571) X
91 1 Pc. Port plate Stainless steel (1.4301)/PEEK X X
92 1 Pc. Thrust plate Stainless steel (1.4301)/
(1.4057) X X
93 5 Pcs. Back-up ring PTFE X X
94 5 Pcs. O-ring (Ø8.73 xØ1.78) NBR X X
121 1 Pc. Port ange with bearing Stainless steel (1.4301)/PEEK
122 1 Pc. O-ring (Ø78 x Ø3.00) NBR X
123 1 Pc. O-ring (Ø75.92 x Ø1.78) NBR X
124 1 Pc. Shaft seal SIMRAX, AX15EA-018,
1.44301/C/AI203 X
125 1 Pc. Front cover Stainless steel (1.4301)
126 2 Pcs. Pin (Ø4.0 x 8.0 mm) A4 X
127 2 Pcs Screw (M5 x 20 mm) A4 X
131 2 Pcs. Plug (G¼"; PA6.6; NV17 Ø20.5) PA
136 2 Pcs. O-ring (Ø7.0 x Ø1.5) NBR X
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 X
150 1 Pc. Stainless steel
- 1 Service instruction (180R9152) X X X X X
4.1. Service kit list for MAH 12.5

Service guide | Disassembling and assembling MAH 6.3 - 12.5
15
180R9152 | AX357937856579en-000402 | 07.2021
5. Exploded view
MAH 6.3

© Danfoss | DHS (im) | 2021.07 180R9152 | AX357937856579en-000402 | 16
Danfoss A/S
High Pressure Pumps
Nordborgvej 81
DK-6430 Nordborg
Denmark
5.1. Exploded view
MAH 12.5