CAUTION
The minimum bend radius is the bend that a hose
will withstand without stressing or kinking. The
hose should be straight for at least one hose di-
ameter before starting to bend. The outside of a
hose may appear smooth even if the inner tube is
kinked. See
IMPORTANT: Ensure that the hoses do not con-
tact the tires or other parts and do not stress or
kink, especially at the metal sleeve, through the
entire range of motion.
9.
Shut down the engine.
10. If the hoses are leaking, contacting the tires or
other parts, kinking, or if the minimum bend ra-
dius is insufficient, replace both front brake
hoses and both front brake chamber fittings. See
Group 42 of the
School Bus Chassis Workshop
Manual
for more information.
42–13 ABS Tone Rings
Cleaning
CAUTION
An accumulation of road salt, dirt, and debris on
the antilock braking system (ABS) tone rings and
sensors can cause the ABS warning light to illumi-
nate.
IMPORTANT: During winter months in areas
where corrosive materials are used on the high-
ways, periodically clean the underside of the
vehicle to ensure proper ABS functioning. Thor-
oughly clean the wheel/ABS sensor/tone ring
areas, removing all corrosive materials.
42–14 Brake Caliper Slide Pin
Lubricating, Bosch
Brakes
NOTE: See the
Bosch Pin Slide Disc Brakes
Service Manual for more information.
Apply 1/8 oz (3.5 g) Aeroshell grade 5 grease to
each of the two guide pin and guide pin bore sets.
See the
Bosch Pin Slide Disc Brakes Service Manual
for additional information.
IMPORTANT: The later ZOH-T caliper has im-
portant differences from the early ZOPS caliper.
ZOPS calipers (since 1998) and ZOH-T calipers
(since 2002) use different slide pins and bolts.
See
and
. The later trailing pin is
identified by notches and has a rubber bushing.
Flanged instead of hexbolts are used with the
later caliper. The later bolts have a fine thread
rather than a coarse thread pitch, are longer,
differently colored, and are tightened to a higher
torque specification. Use only the ZOH-T bolts
to assemble a ZOH-T caliper. The ZOPS caliper
bolts have a different thread pitch and will not
assemble correctly in a ZOH-T caliper mounting.
Also, the ZOH-T bolts will not assemble cor-
rectly in a ZOPS caliper. Do not interchange
parts. It is permissible to use both ZOH-T pins
and ZOH-T bolts in a ZOPS anchor plate, but
they must be replaced as sets. Both the pins
and the bolts must be changed.
XX
DANGER
The correct pins, bolts, and bolt torque must be
used. If not, brake function could be impaired and
lead to loss of control of the vehicle, which could
result in personal injury, death, or property dam-
age.
IMPORTANT: The ZOH-T caliper assembly is
similar in appearance to the existing ZOPS cali-
per. The only obvious difference is that one of
the anchor plate slide pins (trailing side) has
11/03/94
f420329a
A
NOTE: The center of the hose bend radius should be
well away from the fitting.
A. Bend Radius
Fig. 6, Bend Radius
Brakes
42
School Bus Chassis Maintenance Manual, March 2003
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