Peterbilt 325 2017, Operator'S Manual

Page: 183 / 392

OPERATING THE BRAKE SYSTEM
Parking Brake
1. Normal Run Position
2. Trailer Park With Vehicle
Released
3. System Park or Trailer
Charge With Vehicle Parked
Parking brakes work in reverse action
of the regular brakes. When the
parking brakes are engaged, air is
exhausted from the spring chambers
which allow the spring to engage the
brakes. This design also provides for
the safety function if a brake circuit
has a leak and loses air. In such a
scenario, the parking brakes will apply.
The vehicle’s parking brake controls
are the yellow diamond shaped knob
on your dash board. If the vehicle is
equipped to tow a trailer, then there will
be an additional red octagon shaped
knob for the trailer parking brakes.
Parking brakes will be engaged when
either of these knobs are pulled OUT.
(If one knob is pulled out, the other
knob will automatically pop out.)
Pushing IN a knob will disengage
the respective parking brakes. If you
push in the yellow knob only, you
will disengage the vehicle’s parking
brakes but will not disengage the trailer
parking brakes (if applicable). Either
knob will pop back out if the system
pressure is not above 60 psi (414 kPa).
The instrument panel display will
provide a message any time the
parking brakes (vehicle or the trailer)
are set and the vehicle is put into
motion.
(03/17) Y53-6060-1C1
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