Advance acoustic 56514925, Service Manual, Page: 9 / 260

9 Service Manual – Advance 7765 / Nilfisk CR1500
General Information
General Machine Description
Machine Configurations
The Advance 7765 and Nilfisk CR1500 machines are industrial automatic rider sweeper/scrubbers with
multiple sweep/scrub single-pass coverage. The 7765 and CR1500 are all-hydraulically operated and are
equipped with power steering.
The machines are powered by a 3.0 liter, 86-hp GM gasoline or liquid propane gas (LPG) engine, or a 2.5
liter, 47.3-hp Mitsubishi diesel.
The 7765 machines are available in two different hopper configurations; a manual dump (MD) model and a
variable dump (VD) model. The CR1500 machines are only available in the variable dump configuration.
• The manual dump models have a smaller, fixed hopper. A manual dump lever opens the hopper to empty
the hopper onto the floor below the machine.
• The variable dump models use a hydraulic cylinder to raise the hopper for emptying into a dumpster or
other receptacle. A separate hydraulic cylinder opens and closes the hopper dump door. Variable dump
models are also equipped with a hopper filter, dust control motor and impeller, and filter shaker motor.
Hydraulic System
The engine drives two hydraulic pumps that power the machine systems. All of the motors on the machine
are hydraulic except for the electric filter shaker motor.
• The 1.24 cubic inches per revolution (CIR) drive pump is a variable-displacement pump that powers the
rear wheel drive motor for propulsion.
• The dual-displacement auxiliary gear pump includes two separate 1.02 CIR pumping elements in one
unit that power the other machine work functions.
The scrub deck position, scrub brush motors, main broom motor, side broom motor, recovery vacuum motor,
hopper vacuum fan motor and squeegee position are all controlled by hydraulic solenoid valves actuated by
switches on the instrument panel.
The hopper lift and dump door hydraulic cylinders are controlled by mechanically-actuated hydraulic valves.
Drive and Steering Systems
The foot-activated directional control (drive) pedal controls the hydraulic oil flow from the variable-
displacement pump to the hydraulic rear wheel drive motor to determine machine speed and direction. A
hydroback (newer models) or mechanical centering device (older models) returns the pedal to the neutral
position when the pedal is released.
The power steering unit controls the oil flow to the hydraulic steering cylinder. The steering cylinder moves
a rack that turns a spur gear to steer the rear drive wheel.