Operation
Observethefollowingprecautions:
•Nevercoastdownhill.Servicebrakesaloneshouldnot
beusedtocontrolspeedonmajordowngrades.Brakes
willfadefromoveruse.
•Downhillspeediscontrolledbyremovingone’sfootfrom
theacceleratorpedal(enginerunningwithclosedthrottle)
andputtingthetransmission/rearaxleinreducedgear.If
thetransmission/rearaxleisinagearthatresultsinmore
thantheappropriatespeed,aproperdownshiftshouldbe
madetoavoidoveruseofthebrakes.Ifthepropergear
selectionwasnotmadeandthebrakeswereoverused,
thenstopthevehicleandwaitforthebrakestocool.After
thebrakeshavecooled,continuedowngradeinalower
gearrange.
•Thecommonruletofollowinusingtheengineand
transmission/rearaxletocontrolvehiclespeedisto
selectalowergeargoingdownthehillthanwouldbe
requiredtoascendthehill.Therearesomeexceptions,
suchasgoingdownashorthillwithgoodvisibilityand
nohazards.
•Theservicebrakesshouldbeusedtosupplement
availablevehicleretardationmethods.Whendescending
longgradesrequiringuseofthebrakes,shortapplications
(3-5secondsduration)shouldbemaderatherthanlong,
continuousapplications.Thisminimizestemperature
rise,brakefade,andairconsumptionofairbrakesystem.
AirBrakes
GeneralInformation
WARNING
Topreventpersonalinjuryand/ordeath,or
damagetoproperty,ifpartofthebrakesystem
fails,reducespeedandemploysafedriving
practicesasstoppingdistancemayincrease
underthefailedconditionorifonlyonesection
ofthebrakesystemisoperating.Havebrake
systemrepairedimmediately.Lossofbraking
capabilitycouldcauseanaccident.
Thetrucktypescoveredinthismanualareequippedwithasplit
brakesystem.
Thepurposeofthissplitsystemistoprovideameansof
stoppingthevehicleshouldafailureoccurineithertheprimary
orsecondarybrakesystem.Ifairpressurelossoccursinone
system,theremainingsystemcontinuestoprovidebraking
action.
Whenafailureisdetectedtheairdryerisprovidedwithalimp
homefeaturetoallowthevehicletobedriventoaservicecenter.
Ifvehiclehasbeenparkedforanextendedperiodincold
weather,alwayschecktobesureallwheelsarerollingfree
(brakesarenotfrozen)whenstartingout.Alwaysclean
accumulatediceandsnowfrombrakelinkage.
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