Header Drive: Hydraulics; Flow Control Block; Header Drive Relief Pressure - MacDon 9250 Operator's Manual

Header Drive: Hydraulics

FLOW CONTROL BLOCK

Flow control block (A), located under cab near ground speed linkage, provides hydraulic power to the header.
The block divides pump output of 19 gallons per minute (gpm) and controls the flow of oil into two circuits.
Flow is used by the various headers as follows:
Auger Header
Both circuits combine to supply oil to the reel drive. Flow can be varied from 6 to 19 gpm with either reel or
conveyor speed control knob on cab console.
Harvest Header and Multi-Crop Header
The flow to each circuit (reel and conveyor) can be varied from 3 to 9 gpm.

Header Drive Relief Pressure

Overload protection for the reel and conveyor
drives is provided by an internal relief valve in flow
control block (A). Should stalling problems develop
with one of the header hydraulic circuits, check
and adjust relief pressure as follows:
1. Attach a 3000 psi (20 MPa) pressure gauge to a
hose that is long enough to allow pressure
gauge to be read from the operator's seat.
Attach pressure gauge hose to female coupler
(E) at the tractor right hand leg and position the
gauge to be visible from the seat.
2. Set controls as follows:
• Start engine and run at operating speed.
• Move header drive switch to engaged position.
• Adjust reel speed control to minimum. (Reel
should be turning slowly.)
3. Pressure should be 2200 to 2350 psi (15.2 to
16.2 MPa). If not, proceed with adjustment:
4. Move header drive switch to disengaged
position. Shut off engine and remove key.
5. To adjust relief setting:
• Loosen jam nut at relief valve (B).
• Turn the adjustment screw in 1/4 turn
increments, clockwise to increase pressure,
counter-clockwise to decrease.
6. Repeat checking and adjustment until relief
pressure is correct, then tighten jam nut at (B).
IMPORTANT: If relief pressure does not increase
after adjusting the screw two or three times, check
relief valve as follows: Remove relief valve (B)
from flow control block. Check that no contaminant
is preventing the spring-loaded poppet from
properly seating against the valve body. Clean as
required, and reinstall valve. Reset adjustment
screw to original position before checking relief
pressure.
Form # 46584
MAINTENANCE/SERVICE
NOTE: For hydraulic schematics, see
"SCHEMATICS" section at back of this
book.
HEADER DRIVE FLOW CONTROL BLOCK
92
B
HEADER DRIVE FLOW CONTROL BLOCK
E
ATTACH PRESSURE GAUGE
A
Issue 11/06 Web Rev_01