STARTING AND OPERATING THE VEHICLE TRAILER BRAKE HAND VALVE
Regional Haul
(R05/10) Y53-6033 – 113 –
torque. Do not allow the Wheel Spin Control lamp to
remain on continuously for an extended length of time.
Extended, continuous use of the ASR / ATC can cause
overheating of the drive wheel brakes. Engine torque or
vehicle speed should be reduced to eliminate wheel spin
and prevent excessive application of the ASR / ATC sys-
tem.
Except for checking for proper illumination of the ABS and
Wheel Spin Control warning lamps when first starting the
truck and for monitoring these lamps while driving, no
special operating procedures are required. For detailed
system description, see service literature for your specific
ABS that was provided with your vehicle.
Trailer Brake Hand Valve
Tractor/trailer vehicles are equipped with a trailer brake
hand valve mounted on the right side of the steering
wheel column. This hand valve provides air pressure to
apply the trailer brakes only. It operates independently of
the foot treadle valve.
To operate the trailer brake hand valve:
• Pull down on the lever.
• The valve is self-returning. When pressure is
removed from the valve lever, it will return to the OFF
position.
NOTE: The trailer brake is not to be used as a
substitute for the service brakes. Using this brake
frequently, instead of using the foot brake, will
cause the trailer brakes to wear out sooner.
WARNING! Do not use the trailer hand brake
or service brakes to park and hold an unat-
tended vehicle—use the parking brakes.
Because service brakes work with air pres-
sure, these brakes could slowly release. Your
vehicle could roll, causing a serious accident.
Someone could be hurt or killed. Never rely on
the service brakes to hold a parked vehicle.
Driving Bobtail or With an Unloaded Trailer
NOTE: The following information is applicable
only to tractor configurations.
Do not use the engine retarder (such as an
exhaust brake) to slow the vehicle down when you are
bobtailing or pulling an empty trailer.
