Section 12: BRAKE AND AIR SYSTEM
PA1562
18
FIGURE 28: ADJUSTER PINION 12120
FIGURE 29: BOX WRENCH ON ADJUSTER PINION 12118
27.1.3 Roadside Inspection for Knorr/Bendix
Air Disc Brakes
The coach is equipped with air disc brakes and
therefore, cannot be inspected using the
requirements for chamber stroke or visible lining
clearance or lining thickness as specified for
drum brakes. The roadside inspector should use
the following instructions to determine that the
air disc brakes are within proper adjustment and
have sufficient pad wear thickness.
The Knorr/Bendix air disc brake is designed to
move freely, with minimal force, in the axial
direction on the two sliding pins as identified in
figure 30. The movement in the axial direction
should not exceed 2 mm (5/64”).
FIGURE 30: CALIPER AXIAL MOVEMENT 12132
The pad thickness can be seen but would
require removal of the tire and rim. An indicator
of the pad wear condition is available by
inspecting the floating pin location in relation to
the rubber bushing as shown in figure 31. When
pads are in new thickness condition, the pin will
be exposed (C) 19 mm (¾”). When the pads are
worn to replacement conditions, the pin will be
nearly flush to the bushing (D) or within 1 mm
(3/64”) of the edge of the rubber bushing.
FIGURE 31: BRAKE PAD CHECK 12117
27.1.4 Pad Removal
Turn adjuster pinion (23) counterclockwise to
increase pad to rotor clearance (a clicking noise
will be heard). Push caliper toward actuator and
remove pads (12).
CAUTION
Do not apply brakes while pads are removed
as this could cause over stroke damage to the
adjusting mechanism.
FIGURE 32: PAD REMOVAL 12111
27.1.5 Checking Pad Wear
Minimum friction material thickness is 2 mm (A,
Fig. 33)
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