Navistar International LT Series - Parking Brake Indicator

Operation
TheTRAILERAIRSUPPLYvalveknob(RED)andPARKING
BRAKEvalveknobwillautomaticallypopoutifthesystem
pressure(bothfrontandrearcircuits)dropsto20-40psi(138-
276kPa).Thetractorprotectionvalvewillthenclose,thetractor
springbrakeswillapply,andthetraileremergencysystemwill
beactivated.
Onvehiclesequippedwiththestandardtwo-valvesystem,
theoperationofonevalvetogetherwiththeotherpermitsthe
operatortoselectthedesiredfunctionsdescribedbelow:
REDValve
(TrailerAir
Supply)
YELLOWValve
(ParkingBrake)
Function(Mode)
OutOutSystemPark
InOutTrailerCharge
InInNormalRunning
OutInBobtail/SlidingFifthWheel
Adjustment/SlidingTrailer
TandemsAdjustment
ThePARKINGBRAKEvalve(YELLOWknob)controlsthespring
brakesonthetractorandwhenpulledoutsimultaneouslycauses
thetrailersupplyvalvetopopout,thusapplyingbothtractorand
trailerparkingbrakes.Thetrailerbrakemaybeindependently
releasedbypushingonlytheTRAILERAIRSUPPLYvalve(RED
control)in.
TheTRAILERAIRSUPPLYvalve(REDvalve)deliversairto
thetrailersupplyandwillautomaticallypopout,shuttingoffthe
trailersupplyifpressureisdecreasedtoapproximately35psi
(241kPa).Forexactairpressuresetpoints,refertotheService
Manual.
NOTE:Whenattemptingtoreadjust/slidethepositionof
thetractorfthwheelorthetrailer’standemaxleswith
thetractorandtrailerfullyconnected,leavethetractor’s
PARKINGBRAKEpushedinandpulltheTRAILERAIR
SUPPLYout.Thiswillapplythetrailer’sparkingbrakeand
keepitstationarywhilethetractorismovedforwardor
backward.
ParkingBrakeIndicator
WARNING
Topreventpersonalinjuryand/ordeath,
ordamagetoproperty,avoiddrivingwith
theparkingbrakeapplied,whichcanleadto
excessiveheatbuildupandpossiblere.
TheParkingBrakeindicatorisoperatedinconjunctionwiththe
parkingbrake.Withtheignitionswitchonandtheparkingbrake
set,thePARKindicatorwillilluminate.Iftheindicatordoes
notilluminatewiththeparkingbrakeset,theindicatormaybe
inoperative.
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