The scraper hydraulic system has two hydraulic pumps.
The pumps are on the housing for the torque converter,
between the transmission and engine near the left side
of the tractor. Each of the pumps have two sections and
both are vane-type pumps. One of the pumps is for the
hydraulic motor that runs the elevator. The oil from both
sections of this pump is used to run the elevator at HIGH
speed. When the elevator is in LOW speed, the oil from
only one of the pump sections is used. The other two-
section pump is for the steering and the cylinders for the
bowl and ejector.
The control levers for the elevator, bowl and ejector are
at the right side of the seat for the operator. Flexible
cables (with covers) are used to connect the control
levers to the valve spools in the hydraulic control val-
ves. When the control levers are in HOLD position, with
the engine running, all of the oil from the hydraulic
pumps goes through the control valves and back to the
filter in the hydraulic tank. The oil goes through the filter
and then into the tank.
The oil filter has a bypass valve. If the filter element
gets too much dirt and the oil can not easily go through
the element, there is an increase in the pressure of the
oil to the filter. High oil pressure opens the bypass valve
and the oil goes through the open bypass valve into the
tank. Cold hydraulic oil can not easily go through the filter
element. The increased pressure of the cold hydraulic oil
keeps the bypass valve open until the oil gets warm
which decreases the oil pressure and the bypass valve
SCHEMATIC OF HYDRAULIC SYSTEM FOR BOWL DOWN
1. Elevator hydraulic motor. 9. Oil line (for rod ends of
14. Relief valve (elevator
21. Door check valve.
2. Bowl cylinder (two).
22. Pump (elevator).
3. Bowl control valve.
10. Relief valve (bowl oil
15. Ejector cylinder.
A. DOWN position.
4. Carry check valve (two).
16. Oil line.
B. HOLD position.
5. Oil line (for head ends of 11. Oil line (to elevator
17. Oil line (for steering).
C. UP position.
18. Door cylinder.
6. Ejector valve spool.
12. Elevator control valve(in
19. Filter and tank.
7. Elevator speed valve.
20. Pump (bowl and
8. Vent line (for carry check 13. Return oil line.