Hydraulic Proportional Control (Type Hz) - Sauer Danfoss 51 Series Service Manual

Bent Axis Variable Displacement Motors
Minor Repair and Replacement - Variable Motor (Continued)

Hydraulic Proportional Control (Type HZ)

Thoroughly clean external surfaces prior to removal
of control.
Remove the four (4) screws retaining the valve hous-
ing to the end cap with an 8 mm internal hex wrench
(060, 080, and 110 units) or a 10 mm internal hex
wrench (160 and 250 units). Remove the valve hous-
ing. Remove the O-rings between the valve housing
and end cap, and the O-ring on the valve spool
sleeve.
The plugs on the control housing may be removed
with a 7/16" or 11/16" hex wrench. When reinstalling,
torque the 5/16" plugs to 9 Nm (7 ft•lbsf), and the 9/16"
plugs to 37 Nm (27 ft•lbsf)
The valve housing is equipped with filter screens in
the passages between the housing and the end cap.
Units with internal servo pressure supply have a filter
screen installed in the end cap passage leading to the
valve spool sleeve. These screens should be pressed
into position (with the rounded edge of the filter
screens facing "out") until they are flush to 2.0 mm
(0.08 in.) below the machined surface of the valve
housing or end cap.
Units with external servo pressure supply have a plug
installed in the end cap passage leading to the valve
spool sleeve. This plug may be removed with a 2.5
mm internal hex wrench. When installing this plug,
torque to 2 Nm (18 in•lbsf).
Install a new O-ring onto the valve spool sleeve in the
end cap. Install new O-rings onto the end cap.
Install the valve housing onto the multi-function block,
and install the screws.
Torque the screws to 78 Nm (58 ft•lbsf) for 060, 080,
or 110 units, or to 110 Nm (81 ft•lbsf) for 160 or 250
units.
50 - 9
51000080
Fig. 50-42 - Remove
HZ Control Housing
Screws
Fig. 50-44 - HZ Control Components
51000082
Fig. 50-45 - HZ
Control Housing
Screens
51000081
Fig. 50-47 - Install HZ
Control Housing
Series 51
51000081
Fig. 50-43 - Remove
HZ Control Housing
51000016
51000083
Fig. 50-46 - End Cap
O-Rings Installed
51000084
Fig. 50-48 - Torque
HZ Control Valve
Housing Screws
59