THEORY OF OPERATION - CONTINUED
The propel control lever, when pushed forward, causes the roller to go forward. Pull the propel control lever backward
to go in reverse. The propel control lever controls the flow of pressurized hydraulic oil to the propel motors. The hydrau-
lic propel motors, located on the left of the front drum and the right of the rear drum, turn the propel gearboxes which
turn the roller drums. The propel speed switch is a toggle switch that controls whether the propel system operates in
high-speed range (hare) or low-speed range (tortoise) by activating the shift solenoid to change the flow rate of hydrau-
lic oil to the propel gearboxes.
Inside each propel gearbox is a brake which is automatically engaged when there is no hydraulic pressure resulting from
the activation of the propel system in forward or reverse. When the roller needs to be moved while the engine is not run-
ning, a manual brake release pump can be used to release the brakes. Brake and neutral start relays in the system prevent
movement of the roller during the starting procedure.
The power for the propel system comes from a four-cylinder, turbocharged diesel engine mounted in the center of the
roller. The engine is attached to the propel hydraulic pump, which provides the pressure charge for the propel system.
The fuel/hydraulic oil tank consists of the hydraulic tank (located on the left side) and the fuel tank (located on the right
side). Although the tanks are welded together, they are separate in their function. The CB534B Roller hydraulic oil tank
holds 15.5 gallons (59 liters) of hydraulic oil. The CB534C Roller hydraulic tank holds 24 gallons (91 liters) of hydrau-
lic oil. The fuel tank holds 55 gallons (208 liters) of diesel or JP-8 fuel to supply the engine.
PROPEL CONTROL LEVER
FUEL/HYDRAULIC OIL TANK