Bendix Commercial Vehicle Systems ADB22X-V Air Disc Brakes - Manual (Page 7)

7
2.1 BRAKE PAD AND ROTOR INSPECTIONS
Visual checks of the condition of the brake pad/rotor wear
can be made without removing the wheels. Where dust
guards are not used, the top of the pads and part of the
rotor are visible through the opening at the top of the brake.
Other visible portions of the rotor can be inspected at the
same time.
Unless a vehicle has been stored for some time, the main
rotor surfaces that contact the pads will always appear to
be shiny. Surface rust on these surfaces would indicate a
malfunctioning brake that should be inspected immediately.
Pads are 1.181 in. (30 mm.) thick when new and must be
replaced when they reach 0.433 in. (11 mm.). Rotors are
1.77 in. (45 mm.) thick when new and must be replaced
when they reach 1.46 in. (37 mm.). See Section 4.3 for
further inspection criteria.
2.1.1 Electronic Wear Indicators
Use the dash indicator(s) and/or a hand-held diagnostic
tool to regularly monitor the pad wear. (See Section 5.2.)
2.1.2 Mechanical Wear Indicators
See Figure 9 for the location of the mechanical wear
indicators. There are two types (See Figure 10 for Style A
and Figure 11 for Style B).
Location of Wear
Indicator Notches
(Both sides of brake)
Quick Visual
Inspection of Pad
Thickness and Rotor
FIGURE 9 - LOCATION OF WEAR INDICATORS
Note: These mechanical wear indicators do
not constitute “out-of-service” criteria. These
inspections only show when to schedule a full wheel-
removed inspection of the brake pads and rotor.
The thicknesses of the pad and rotor will both affect
the wear indicator position at which maintenance is
actually needed.
Wear Indicator Style A:
Where both the carrier and caliper have an
indicator notch.
Compare the relative position of two notches cast into
the carrier and caliper. When the two notches align,
it is time to schedule a full wheel-removed inspection
of the pads and rotor.
Notch in the
caliper
Notch in the
carrier
When the notches
line up, it is time
to schedule an
inspection of the
pads and rotor
FIGURE 10 - STYLE A - WHEN BOTH CARRIER AND CALIPER
HAVE A CAST NOTCH
Wear Indicator Style B:
Where only the caliper has an indicator
notch.
When the notch in the caliper aligns with the front
edge of the torque plate, it is time to schedule a full
wheel-removed inspection of the pads and rotor.
Torque
plate
No notch
in the
carrier
Notch in
the caliper
When the
torque plate
edge lines up
with the notch,
it is time to
schedule an
inspection of
the pads and
rotor
FIGURE 11 - CARRIER WEAR INDICATOR NOTCH AND BACKING
PLATE ALIGNMENT