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BRAKES
There are two (2) brake systems on your vehicle,
the
service
brakes
emergency & parking brakes, both of which are
described below.
Your vehicle may also be supplied with ABS
brakes (antilock braking system) and an additional
retardation
system.
information is available in this section on page 3-
2;
for
information
retardation systems, see "ENGINE RETARDER
SYSTEM
(JACOB)"
"AUTOMATIC
TRANSMISSION
RETARDER" on page 4-5.
Service brakes
The service brakes use air pressure from a
footpedal-operated master cylinder to actuate
cylinders which apply the brakes at each wheel.
The air system is divided into two (2) independent
circuits to isolate front brakes from rear brakes,
thus providing safe braking if one (1) circuit fails.
Front axle brakes operate from the secondary air
system, while brakes on both the drive axle and
tag axle operate from the primary air system.
NOTE: The tag axle service brakes operate only
when the axle is in normal ride position (loaded &
down).
Furthermore, the brake application sequence,
which starts with rear brakes and then front
brakes, provides uniform braking on slippery
surfaces.
For safe brake effectiveness, vehicle air system
pressure should reach at least 95 psi (655 kPa) in
both primary and secondary air circuits.
(see items #14 & 19 on page 2-9)
A warning light turns on (see Dashboard items #7
& 8, page 2-9) and a buzzer sounds when
and
the
combination
ABS
brakes
system
regarding
both
optional
on
page
4-4
OUTPUT
XL Series Motorcoach
█
airpressure in one of the primary or secondary
circuits drops below 60 psi (413 kPa). Vehicle
must then be stopped and cause of pressure loss
must be corrected before further operation.
WARNING:
pedal is not recommended. This practice will not
increase brake system effectiveness, but will
instead waste air and thereby reduce brake
effectiveness.
"RIDING" the brake by resting foot on brake pedal
when not braking can cause abnormally high
and
brake
temperatures,
possible damage to the brake drums, and loss of
brake efficiency.
Combination emergency and parking
brakes
Emergency brakes
In normal operation, if air pressure in both brake
circuits drops below approximately 40 psi (276
kPa), spring-loaded emergency parking brakes
will immediately be applied at full capacity on drive
and tag axle wheels to stop vehicle (tag axle
emergency brakes
vehicles).
emergency brakes might be applied quite rapidly.
Vehicle must then be stopped and cause of
pressure loss must be corrected before resuming
operation.
Parking brakes
Spring-loaded parking brakes
applied by pulling up the control valve knob,
located on R.H. lateral console (see page 2-20).
They are not designed to be used as service
brakes. In normal driving conditions, control valve
knob must be pushed all the way down.
3 - 1
SAFETY
"FANNING" or "PUMPING" brake
excessive
lining
are
optional
In
an
extreme
condition,
are manually
wear,
on
XL-40
the
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