Functional And Visual Check; Wear Check Of Pads - PREVOST H3-41 Maintenance Manual

SECTION 12: BRAKE AND AIR SYSTEM
18.2

FUNCTIONAL AND VISUAL CHECK

18.2.1 Wear Check of Pads

The thickness of the pads must be checked
regularly dependent on the usage of the vehicle.
The pads should be checked corresponding to
any legal requirements that may apply. Even if a
wear indicator is fitted and connected, this must
be at least every 3 months.
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.
FIGURE 20: MINOR BREAKOUTS AT THE EDGES ARE
PERMITTED (SEE ARROW)
FIGURE 21:MAJOR BREAKOUTS ON THE SURFACE OF
THE BRAKE PAD ARE NOT PERMITTED
30 PA1621 Maintenance Manual All Series | Revised June 2020
If the thickness of the friction material at its
thinnest point is less than 0.079 inch or 2 mm
(measurement C), the pads must be replaced.
A= Overall thickness of new brake pad: 1.181
in (30 mm)
B= Backplate SN7 type: 0.354 in (9 mm)
C= Minimal thickness of friction material:
0.079 in (2 mm)
D= Minimum allowed
condition for
material: 0.433 in (11 mm)
FIGURE 22: BRAKE PADS DIMENSIONS
Exaggerated wear difference between inner
and outer brake pads
The total thickness of the friction material of the
inner and outer pad should be equal. If the
difference between the two pads is greater than
3.5 mm, then the
necessary:
• Bearing clearance check (see 18.2.7 &
18.2.8).
• Free movement of the brake pads in the
caliper (see 18.2.6).
• Possible collision with other parts on the
axle or vehicle body.
• Excessive dirt and grime present.
• Piping of the compressed air line
Example 1)
E=0.748 in (19 mm)
F=0.590 in (15 mm) > NOT OK
thickness in worn
backplate and friction
following checks are