MacDon 9250 SP - Manual (Page 99)

Form # 46584 Issue 11/06 Web Rev_01 97
MAINTENANCE/SERVICE
Traction Drive: Hydraulics
TRANSMISSION OIL PRESSURE
Warning light and buzzer in cab will be activated
when ignition switch is turned ON if transmission
oil pressure is below approximately 40 psi (275
kPa) for Naturally Aspirated engine and 150 psi
(1035 kPa) for the Turbo engine. Do not drive the
windrower until light and buzzer go off. If light and
buzzer stay on after engine starts, or if they
activate during operation, shut engine off and
check hydraulic oil level at reservoir. If oil level is
adequate, measure charge pump pressure as
described below.
CHARGE PUMP PRESSURE
The charge pump provides hydraulic power to the
traction drive. To check charge pump pressure:
1. Remove supercharge line at (A). This line runs
between “SC” port on manifold and
transmission pump. Place a tee capable of
accepting a pressure gauge in the line.
2. Attach a 0 - 600 psi (4000 kPa) pressure gauge
to a hose that is long enough to allow pressure
gauge to be read from the operator's seat.
Attach hose to the tee inserted in Step 1.
3. Start engine and move throttle lever fully
forward. Pressure should be:
• 150 to 170 psi (1035 to 1170 kPa) for
Naturally Aspirated units
• 200 to 230 psi (1380 to 1585 kPa) for Turbo
units (except Australian).
• 270 to 290 psi (1860 to 2000 kPa) for
Australian Turbo units.
If pressure is not within this range, adjust relief
pressure as follows:
4. Shut off engine and remove key.
5. To adjust relief setting:
• Remove cap from relief valve (B) for access to
adjustment screw.
• Loosen jam nut at adjustment screw.
• 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 and
replace cap 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.
NOTE: For hydraulic schematics, see
“SCHEMATICS” section at back of this book.
A
INSTALL TEE IN SUPERCHARGE LINE
B
CHARGE PUMP RELIEF VALVE