Kohler K91 Owner's Manual page 326

GENERAL INFORMATION
This manual covers the overhaul of the hydraulic
lift control valves listed below.
102874
&
10668 1 (OMCO) Fig. 1
-
1973 18
HP
Automatic, 1974-80 D-Series Automatic
tractors with Sundstrand hydrostatic transmission.
lift
system pressure is regulated by an implement
relief valve located in the hydrostatic transmission.
103204
&
106680 (OMCO) Fig. 1
-
1973 16 HP and 1974-80 C-Series Automatic trac-
tors with Sundstrand hydrostatic transmission. lift
system pressure is regulated by an implement relief
valve located in the hydrostatic transmission.
108494 (OMCO) Fig. 2
-
1980-82
C &
GT-Series Automatic tractors with
Eaton hydrostatic transmission, except C-195. l i f t
system pressure is regulated by an implement relief
valve located to the right of the valve handle.
109679 (OMCO) Fig.
2
-
1982-83 C-195 Twin Automatic tractors. l i f t system
pressure i s regulated by an implement relief valve
located next to the outside valve handle.
110068 & 11 1066 (VICTOR) Fig. 11
-
1983
&
later
C &
GT-Series Automatic tractors with
Eaton hydrostatic transmission, except C-195. AI-
though the valves are made by different vendors
and require different overhaul
kits,
they are inter-
changeable as complete assemblies. l i f t system
pressure i s regulated by an implement relief valve
located next to the valve handle.
110492 (VICTOR) Fig. 11
-
1984
&
later C-195 Twin Automatic tractors with
Eaton hydrostatic transmission. l i f t system pressure
i s regulated by a relief valve located next to the
inside valve handle.
MANUFACTURING DATE CODE (OMCO)
The month and year a particular hydraulic valve
was manufactured is stamped on the flat side of the
outlet cover as shown in Figures 1
&
2. One or two
lines of information may be on the cover, which are
decoded as follows:
Example (on all valves): 0948 1 9
Example (on some valves): SR115 4
0
Manufacturer's Control numbers
Month Built
Year Built
(1
=
January; 12
=
December)
(9
=
1979;
0
=
1980; 1
=
1981, etc)
VALVE DESCRIPTION (OMCO)
The hydraulic control valves are made up of one
or two spool valves and bodies, secured between an
inlet and outlet cover. Normal working pressure i s
500-700 PSI. Sundstrand implement system pressure
can be field adjusted. On Eaton systems the implement
relief valve is part of the control valve and i s factory
set at 700
PSI
-
do not attempt to alter this setting.
Severe transmission damage may result. Refer to the,
applicable repair manual for system pressure tests
and adjustments.
When the valve handle
is
moved to push the spool
valve inward, hydraulic port "A" i s pressurized and
port
"B"
i s connected to the outlet port (Fig. 3). When
the spool valve is pulled outward, hydraulic port "B"
is pressurized and port "A" i s connected to the outlet
port. The spool valve is spring loaded to return to a
middle, "neutral" position, where ports "A" and
"B"
are sealed off from both the pressure and outlet ports.
These are open-center valves, so hydraulic oil i s free
to flow from the pressure port to the outlet port when
the spool i s in neutral. Attachment "float" i s accom-
plished mechanically by the tractor's
lift
linkage.
MANUFACTURING DATE CODE
I03204 & I 06680
VALVE
102874
& 106681
VALVE
FIG 1. OMCO
Control Valves
(Sundstrand Transmission)
MANUFACTURING DATE CODE
108494 VALVE
109679 VALVE
IMPLEMENT RELIEF
VALVE
FIG. 2. OMCO
Control Valves
(Eaton Transmission)
PRESSURE INLET
FROM TRANS.
OUTLET
TO
T R A N S .
FIG.
3.
OMCO
Valve
Port
Identification
- 1 -