THEORY OF OPERATION

TM 9-2510-247-13&P

0003 00

THEORY OF OPERATION

KINGPIN

Removable Kingpin. Two are provided, one is 3.5 inch (88.9 mm), the other is 2 inch (50.8 mm),

for fifth wheel plate and kingpin coupling. For kingpin used with prime mover and placement on fifth

wheel towing device, see WP 0034, Kingpin Placement.

HYDRAULIC FLOW VALVE

Hydraulic Flow Valves Adjustment. Located on hydraulic safety valves on center mast. This

procedure for flow valve adjustment is to be used from 120°F to -50°F (49 °C to -46°C). As oil

viscosity varies with temperatures, it will be required to change the hydraulic flow valve for the

boom and mast functions. The adjustment is made at the flow control knobs located on the

hydraulic safety valves located on the front side of the center mast frame. To adjust, turn control

knob COUNTERCLOCKWISE TO LOWER back pressure and CLOCKWISE TO INCREASE back

pressure. System should maintain 300-800 psi back pressure when the boom or mast is operated,

using MAST RETRACT or BOOM EXTEND with no load. The hydraulic flow valves will

need to be adjusted as necessary as temperatures vary or when OHA 5606 is replaced with

standard hydraulic fluid (reference WP 0004, item 7).

END OF WORK PACKAGE

0003 00-1