TM-9-2320-273-10

TRUCK, TRACTOR, LINE HAUL; LIGHT EQUIPMENT TRANSPORTER; TRUCK CHASSIS; MEDIUM EQUIPMENT TRANSPORTER

TECHNICAL MANUAL; OPERATOR’S MANUAL

DECEMBER 2012

TM-9-2320-273-10 - Page 112 of 452

Table 11. Tractor and Trailer Parking Brake Controls

.

1

2

Figure 11. Tractor and Trailer Parking Brake Controls.

Key

Control/Indicator

Function

1.

TRAILER AIR

SUPPLY Control

(M915, M916, M917,

M920, and M915A1)

CAUTION

If air system pressure drops to 60 psi (414 kPa) as a

result of a release of system pressure or an air leak,

the trailer air supply protection valve will

automatically trip and apply the trailer spring brakes

to prevent the tractor spring brakes from locking up.

Failure to stop tractor and allow air system pressure

to build up will result in damage to equipment.

This control is a valve used to supply compressed air

to the trailer air reservoirs and brakes. Whenever the

SYSTEM PARK control is pulled out to apply the

tractor parking brakes, the TRAILER AIR SUPPLY

control knob will automatically pop out to apply the

trailer brakes. To release the trailer brakes, push in the

TRAILER AIR SUPPLY control knob after releasing

the tractor parking brakes.

TM 9-2320-273-10

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