MIL-T-62246 Truck, Dump, Street Maintenance, Diesel And Gasoline Engine Driven, 21,000 Pounds Gvw, 4X2, CommericalThis specification covers diesel and gasoline engine driven, four-wheel, two-rear-wheel drive dump trucks equipped with a material sprayer, an auxiliary engine driven air compressor, and a vibrating roller for use in street maintenance. Vehicles shall have a minimum gross vehicle weight GVW of 21,000 pounds for normal operating conditions. Vehicles procured under this specification are commercial items which shall be warranted by the manufacturer as specified in acquisition documents.

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MIL-T-62246B(AT)

(a)        Air compressor, unloader-head type, engine driven and engine lubricated, air or water cooled, and having a capacity of not less than 7-1/4 cubic feet per minute (cfm)

*        (b)    Air storage reservoir(s), each tank equipped with drain, and with safety and check valves between the compressor and the last reservoir tank

(c)     Foot control, suspended or treadle type

(d)    Air control valves

(e)     Air pressure gage, visible to the driver

(f)     Low air pressure warning, visible and audible

(g)    Service brake stop lamp switch

(h)    Automatic moisture ejector

(i)     Automatic slack adjusters.

*    3.4.11.2.1  Air dryer.  A replaceable cartridge desiccant type air dryer shall be installed in the air brake system.  The dryer shall have the capability of removing not less than 95 percent of the moisture in the air being dried.  The dryer shall have a precooler and a filter to screen out oil and solid contaminants.  The dryer shall have an automatic self-cleaning cycle and a thermostatically controlled heater to prevent icing of the purge valve.

3.4.11.3  Trailer brake control system.  When specified (see 6.2), in addition to the components specified in 3.4.11.2 and 3.4.11.2.1, a trailer brake control system shall be furnished. The trailer brake control system shall include:

(a)     Identification of emergency and service lines

(b)    Coincident control of trailer brakes with prime mover foot control

(c)     Independent hand control for trailer brakes

(d)    Prime mover protection valve with dash control and automatic breakaway feature

(e)        Trailer stoplight control operable with foot brake and with hand control for trailer brakes

(f)        Two SAE J844 coiled air hoses, not less than 110 inches long when fully extended, with SAE J318 gladhand couplers on both ends of hoses.  The hoses shall be

packaged and stowed in the vehicle tool compartment for shipment

(g)    Air connectors for trailers with SAE J318 gladhand couplers mounted at the rear of

the vehicle, located to prevent interference with trailer

(h)    Dummy gladhand couplers with chains

(i)        Prime mover only parking brake valve to permit prime mover parking brakes to be applied while charging the trailer air brake system.

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