MacDon 873 Combine Adapter - Manual (Page 32)

Form # 147069 Issue 09/06 30
MAINTENANCE/SERVICE
HYDRAULIC SYSTEM (continued)
Flow Control Relief Pressure
The valve on the combine adapter has three relief
valves for the following functions:
(R1) – 3500 psi (24.1 Mpa) – Feed Draper and
Drum in reverse.
(R2) – 3200 psi (22.1 Mpa) – Feed Draper and
Drum in forward.
(R3) – 2500 psi (17.2 Mpa) – Header Side
Drapers.
A possible cause of insufficient draper/drum speed
is low relief pressure.
WARNING: To avoid bodily injury
from bursting hoses and/or
exploding components, do not
continue closing needle valve if pressure
reading exceeds recommended pressure by
more than 150 psi (1.0 Mpa).
To check header side draper relief pressure:
1. Detach draper drive hoses between adapter
and header. Connect orange to blue at header
for storage.
2. Attach a test fixture consisting of a 5000 psi
(34.5 Mpa) pressure gauge and needle valve
between the orange colour coded hose and the
blue fitting at (A) on adapter. Locate the needle
valve closest to the valve block.
3. Set flow control knob (B) to maximum (number
9 on dial).
4. Run combine engine at operating speed.
5. Engage header drive.
6. Close needle valve until flow stops. Pressure
reading should be 2500 psi (17.2 Mpa).
7. Adjust relief pressure at valve (R3) as required.
To adjust relief valves (R1), (R2) or (R3):
• Loosen jam nut on relief valve.
• Turn relief screw until relief pressure is correct.
• Tighten jam nut.
To check adapter drum & feed draper relief
pressure:
1. Attach a test fixture consisting of a 5000 psi
(34.5 Mpa) pressure gauge and needle valve
between the hose and the lower port of the
feed draper motor at (D). Locate the needle
valve closest to the motor.
2. Attach a 5000 psi (34.5 Mpa) pressure gauge
to service port in tee fitting at (E).
3. Run combine engine at operating speed and
engage feeder house drive in forward.
4. Close needle valve until flow stops. Pressure
reading at pump (E) should be 3200 psi (22.1
Mpa).
5. Adjust relief pressure at valve (R2) as
required.
6. Open needle valve.
7. Disengage feeder house drive and reengage
in reverse.
8. Close needle valve until flow stops. Pressure
reading at draper motor (D) should be 3500
psi (24.1 Mpa).
9. Adjust relief pressure at valve (R1) as
required.
10. Adjust sequence valve if required. See pg. 28.
R1
R2
R3
RELIEF VALVES –
READ GAUGE AT (A) FOR VALVE R3
A
B
E
READ GAUGE HERE FOR VALVE R2
D
READ GAUGE HERE FOR VALVE R1