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MAINTENANCE/SERVICE
Hydraulic
System:
Header & Reel Lift
CYLINDER CONTROL VALVE
RELIEF
PRESSURE
Control valve
(A)
directs hydraulic flow to the lift
cylinders.
Depending on header
type,
this
open-
center
valve
will vary in
size
from one to
four
sections,
plus an unloading section which directs
flow back to tank when no cylinders are being
activated.
The control valve
relief
pressure is factory
set at
2000 psi (13.8
MPa),
sufficient for all header
sizes
and
options.
Should lift capacity problems
be
encountered,
the probable cause is low relief
pressure.
To
check and adjust cylinder control valve relief
pressure:
1. Lower header and reel
fully,
stop engine and
remove key from
ignition.
2.
For header lift (and header attitude)
cylinders,
remove the hose from the bottom port of the
cylinder.
For reel lift cylinders, disconnect reel lift line
quick coupler at tractor right hand
leg.
3.
Attach a 3000
psi
(20 MPa) pressure gauge to
a hose
that
is long enough to allow
pressure
to
be read from the operator's
seat.
Attach hose
to cylinder or quick coupler (see step 2) and
position the gauge near the seat.
4. Start engine and move throttle lever fully
forward. Activate the lift control for the circuit
you have tapped and check gauge pressure
reading.
s.
Pressure should be 2000 psi
(13.8
MPa).
If
pressure is not as specified, proceed with
adjustment:
6.
Lower header and reel
fully.
Stop engine and
remove
key.
7. To adjust
relief
setting:
• Remove cap (B) from relief valve on unloading
section of control
valve.
NOTE:
Cap is tight fitting, but not
threaded.
• Tum the adjustment screw in 1
/
8 tum
increments, clockwise to increase relief
pressure, counter-clockwise to decrease.
8.
Repeat checking and adjustment procedure
until relief pressure is correct.
92
CYLINDER CONTROL VALVE
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