PREVOST X3-45 2016 - Checking Disc Brake Pads; Drive Axle - Equipped with a Solid Rubber Bushing and Exposed Guide Pin; Front and Tag Axle - Equipped with L-Bracket Wear Indicator; Vehicles Equipped with a Continuous Wear Sensor

Section 12: BRAKE AND AIR SYSTEM
Section 12 Updated Sept. 2015 X3-45 Commuter PA1593 DOB 2400-2489 15
chambers have a 14 or 16 square inch effective
area for service. The Knorr-Bremse SN7000
brakes are supplied with automatic clearance
(slack) adjusters as standard equipment for
easier adjustment. For more information on disc
brake components and scheduled maintenance,
refer to Knorr-Bremse Service Manual.
27.1 CHECKING DISC BRAKE PADS
Brake pads have to be checked on a regular
basis depending on the vehicle operation. The
remaining thickness of the pads should never be
less than 0.079 in (2 mm). When replacing brake
pads, all four pads on an axle have to be
changed at the same time. There is no inner or
outer pad, since all pads are the same. Once
removed, worn pads should be replaced in their
original position.
27.1.1 Drive Axle – Equipped With a Solid
Rubber Bushing and Exposed Guide Pin
The condition of the pads can be visually
determined without removing the wheel by
checking the position of the caliper (1) compared
to the fixed guide pin (4).
MEASUREMENT “C” WITH NEW BRAKE PADS AND
DISC
MEASUREMENT “C” WITH WORN DISC/BRAKE PADS
FIGURE 24: BRAKE PAD WEAR CHECK ON DRIVE AXLE
If measurement “C” is less than 0.039" (1 mm),
this condition requires a check of the brake pad
thickness and the brake disc with the wheel
removed. If any minimal tolerance limits have
been reached, the pads and/or disc must be
changed.
27.1.2 Front and Tag Axle – Equipped With L-
bracket Wear Indicator
The condition of the pads can be visually
determined without removing the wheel by
checking the position of the caliper compared to
the tip of the wear indicator.
If the side of the caliper (flat surface around
guide pin cap) lines up with the tip of the wear
indicator (i.e. measurement A would be 0.0 in),
the brake pad thickness and the brake disc must
be checked with the wheel removed. If any
minimal tolerance limits have been reached, the
pads and/or disc must be changed.
FIGURE 25: BRAKE PAD WEAR CHECK ON FRONT AND
TAG AXLE
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27.1.3 Vehicles Equipped with a Continuous
Wear Sensor.
These vehicles have a potentiometer installed
directly on the brake caliper.