Service Manual

Hydro-Gear BDP 10
This pump is a variable output axial piston
design with a maximum output of 0.61 cu. in.
(1
0 cc) per revolution. This pump uses a gerotor
charge pump to pre-charge the system.
This is used in a separated pump and wheel
motor system. Hydraulic lines connect the pump
with a wheel motor.
Ross MF Series Wheel Motor
The Ross wheel motor is an internal gear
(gerotor) design. The displacement is 12 cu.
in./rev (196.7cc/rev. A separate pump
is used
to provide the pressure and flow to this motor.
A small displacement pump is used to drive the
wheel motor. The pump must complete several
revolutions to displace enough oil to drive the
wheel motor through one revolution. This
provides a speed reduction similar to using
reduction gears in a mechanical transmission.
Sundstrand Series 15
The Sundstrand Series 15 uses an axial piston
variable pump with a fixed displacement axial
piston motor. The maximum pump output is
.91cu. in. (14.9 cc) per revolution and the motor
displacement is .91cu. in. (14.9 cc) per
revolution. An internal gear (gerotor) charge
pump provides 4.6 gal/min (17.4 l/min).
[.33 cu.
in. per revolution (5.4cchev)] flow for use with a
hydraulic attachment lift.
25
1.1311.11
1.1311.11
1.1311.8
Productivity Series