MacDon 9200 - Hydraulic System: Header & Reel Lift; Cylinder Control Valve Relief Pressure

MAINTENANCE/SERVICE
Hydraulic
System: Header & Reel Lift
CYUNDER CONTROL VALVE REUEF PRESSURE
Control valve (A), located under the RjH tractor
floorboard, directs hydraulic flow to the header lift
cylinde rs, reel lift cylinders and the cylinder used
to engage the clutch for the sickle drive.
The control valve
relief pressure is pre-set to be
sufficient
for all header sizes and options. Should
lift capacity prob l ems deve l op , check and adjust
cyli nder control valve relief pre ss ure as follows:
1. Lower header and reel fully. stop engine and
remove key from ignition.
2. The same relief valve protects both the header
and reel lift circuits. It [s most convenient to
check relief pressure In the reel lift circuit.
For tractors with reel lift hydraulics. reel lift
qu ick coupler (6) is located at left hand leg.
For tractors without reel lift hydraulics. the
header litt circuit may be tapped at Port .C" of
the
11ft valve. Remove hose (e) to access port.
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 quick coupler or valve (see step 2) and
position the gauge to
be visible from the seat.
4.
Start engine and position throttle lever fully
back ~ow idle). Activate the lift control for the
circuit you have tapped (reel or header) and
check gauge pressure reading.
5. Pressure should be
1800 to 2100 psi (12.4 to
14.5 MPal. If not , proceed with adjustment
6. Lower header and reel fully.
Stop engine and
remove key.
7. To adjust relief setting:
• Loosen jam nut at relief val ve (D) .
• Tum the adjustment screw in 1/ 4 tum
increments. clockwise to increase relief
pressure, counter-clockwise to decrease.
NOTE: 1/4 turn = approx. 80 psi change
8. Repeat checking and adjustment until
relief
pressure is correct, then tighten jam nut at (D) .
IMPORTANT: If relief pressure does not increase
after adjusting the screw
two or three times. check
relief valve as follows: Remove relief valve (0) from
control valve block. Check that no contaminant is
preventing the spring-loaded poppet from properly
seating against the
valve body . Clean as required,
and reinstall valve.
Re set adjustment screw to
original position before checking relief Dressure.
86
REEL UFT QUICK COUPLER
)