M+S MM Series User manual

SERVICE MANUAL
Hydraulic Motors type MM
and MLHM
2008

Сервизно ръководство
Демонтаж
Хидравлични мотори Тип GW…
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Service Manual
Disassembly
Hydraulic Motor type MM, MLHM
- 3 -
Instructions in this manual are for MM and
MLHM motors.
Cleanliness is extremely important when
repairing these motors. Work in clean area!
Before disassembly, drain oil from motor.
Remove key when used. For motors with
drain unscrew drain plug and remove washer (O-
ring for MLHM…4,5,7,8).
Although not all drawings show the motor in
disassembly devise (vise), we recommend that
you keep motor clamped during disassembly.
To ensure correct assembling make a
marking line across the motor parts.
1. For F-flanged motors only! Unscrew the
screws M6x14 and remove flange.
2. Place the motor in disassembly devise with
output shaft down.
Fig. 1
3. Unscrew screws using S6 Allen head
spanner. Remove washers (see Figure 1).
Note: The screws are assembled with Loctite
to hold them in place. A higher torque is required
to break screws loose.
4. Remove end cover.
Fig. 2
5. Remove plate. Remove O-ring from plate
groove (For MM 8 the plate has O-rings from
both sides!) Remove balls (2 pcs.) (see Figure 2).
Fig. 3
6. Remove the roll-gerotor set carefully to
prevent dropping of rotor from stator. Do not
dismount!
Remove O-rings from gerotor set grooves
(see Figure 3).
Fig. 4
7. Remove cardan shaft (see Figure 4).
8. Remove distributor plate. Remove O-ring
from plate groove (For MM 8 the plate has O-
rings from both sides!)
Reposition motor in disassembly devise with
shaft upwards.
9. Unscrew screws using S5 Allen head
spanner (see Figure 5).
Screw
Washer
EndCover
Gerotor
Set O-Ring
O-Ring
Plate O-Ring
Ball
Distributor
Plate
Cardan
Shaft
O-Ring

Service Manual
Disassembly
Hydraulic Motor type MM, MLHM
- 4 -
Fig. 5
10. Remove Front cap from housing. Dust
seal and Shaft seal will come off with cap.
Fig. 6
11. Remove with screwdriver Dust seal and
Shaft seal from Front cap (see Figure 6). Work
from outer side for both seals.
12. Remove shaft from housing.
13. Remove thrust washer and needle bearing
from shaft.
1. CLEANING:
Wash all parts (except seals) in a weak
solvent on carbon base and then degrease.
2. MEASURING AND REPLACEMENT:
Measure all parts and compare actual
dimensions with the nominal ones given in the
technical documentation. Replace any parts
with scratches or burrs that could cause leakage
or damage with new ones. Use new seals when
reassembling motor.
3. LUBRICATION:
Lubricate all seal parts which should be
reassembled with light film of petroleum jelly.
Seal Kits:
SK41 5129 0080 for MM…
SK41 5129 1408 for MM…P
SK41 5129 1809 for MM…D
SK41 5123 0001 for MLHM…
SK41 5123 0003 for MLHM…4(7)
SK41 5123 0649 for MLHM…P
SK41 5123 0653 for MLHM…4(7) P
SK41 5123 1297 for MLHM…D
SK41 5123 1299 for MLHM…4(7) D
FrontCap
Washer
ScrewM6x16
Thrust
Washer
Axial
Needle Bearing
O-Ring
Housing
O-Ring
Dust Seal Front Cap
Shaft Seal

Service Manual
Reassembly
Hydraulic Motor type MM, MLHM
- 5 -
To ensure correct assembling orient motor
parts according to previously drawn marking
line.
1. Lubricate output shaft with hydraulic oil.
2. Lubricate lightly all internal housing
surfaces with hydraulic oil. Mount shaft in
housing.
3. Place the motor in reassembly device with
output shaft up.
4. Install needle bearing, then thrust washer
on the shaft.
Place front cap on clean soft surface.
Lubricate shaft seal and dust seal with light film
of clean petroleum jelly (Shell Retinax Grease
HDX2).
5. Place shaft seal in the front cap and firmly
push with Seal driver (see Fig.7).
Fig. 7
6. Turn on the front cap to 180o. Carefully
press dust seal into place. Lips of shaft seal and
dust seal must face outward. Lubricate the O-
ring and fit it to the front cap.
Important: Check seal condition after
installing in housing. If damaged, cut or
improperly installed, replace with new ones.
7. Install the front cap incl. assembled seals
on the shaft. Prevent the seals against damages.
8. Install in the front cap 6 screws M6x16 with
washers and alternately torque them to 8÷10 Nm
(see Fig.5).
9. Reposition motor in reassembly devise with
shaft down.
10. Install cardan shaft into splines of output
shaft.
11. Lubricate and install O-ring in the groove
of the distributor plate (see Fig.3). Install the plate
with O-ring side to the housing.
Timing Procedure
Fig. 8
12. Lubricate O-rings (2 pcs.) and place them
in seal grooves of both stator sides.
13. Place gerotor set on distributor plate
aligning any star point with the shaft key groove
(tooth of external spline) (see Fig.8).
Reverse Rotation: Reverse rotation is obtained
by aligning any star valley with the shaft key
groove (tooth of external spline)
14. Stave 2 chamfers by the side of groove for
O-ring 54,5x1,5 using a hammer, stamp and 5
CW CCW
B AB A
Shaft
Seal
Dust Seal Front Cap
O-Ring
Seal
Driver
Press
Star
Point
Cardan
Shaft
Gerotor
Set
Output
Shaft
Star
Valley
Key
groove
(toothofspline)

Service Manual
Reassembly
Hydraulic Motor type MM, MLHM
- 6 -
mm ball. Lubricate and install O-ring in the
groove of the plate. Install the plate with O-ring
side to the cover. Align the screw holes in the
plate with the screw holes of the gerotor set.
Place the balls into the plate. (see Fig.2).
Note: For MM8 and MLHM8 version the
plate has two O-ring grooves.
15. Install the end cover (see Fig.1). For end
covers “S”, “PL(R)” and “D” orient the port
face right to the name plate of the housing !
16. Install in the end cover screws with
washers and alternately torque them to 2,5÷3
daNm. Before mounting the screws apply 2 or 3
drops of LOCTITE 222 or 243 at top of thread.
17. Install washer (O-ring for
MLHM...4,5,7,8) on drain plug. Tighten plug
with S4 Allen wrench with torque 0,8÷1 daNm.
18. For “F”-flanged motors install in the
flange 3 screws M6x14 torque them to 5÷6 Nm.
19. Install key in shaft key groove.
Disassembly and reassembly of MMP...L(R), MMD, MLHM...PL(R) and MLHM...D (with
integrated Crossover Relief Valve):
These motors are the same as the standard motors except end cover. Follow the same disassembly
and reassemble procedures as for the standard motor.
Disassembly: Unscrew Valve seat and Plug using a S19 wrench. Remove and clean the other parts .
Remove the O-rings from the grooves of the Valve seat and the Plug (see Fig.9A and 9B).
Fig. 9A
Fig. 9B
Reassembly: Install O-rings 11,2x1,8 and 9x1,8 in the relevant grooves of valve seat. Lubricate the
valve and mount it into the valve seat hole, place on it the rest with the slot directed to its conical part.
Screw the valve seat in the housing acc.to the required side for protection (L or R) with 2÷2,3 daNm
torque using a S19 torque wrench.
Install O-ring on the plug. Mount the washer and spring in the inner hole of plug. Tighten plug
with S6 torque wrench with torque 2÷2,3 daNm.
PlugO-Ring
Washer
Spring
Reset
Valve Seat
O-Ring
O-Ring
Valve
EndCover "D"
Reset
Valve
O-Ring
O-Ring
Valve Seat
Spring
Washer
O-RingPlug
Plug
Washer
EndCover "PL"
Spring
Washer
Plug
O-Ring
Valve
Reset
O-Ring
O-Ring
Valve Seat