Brakes Too Sensitive:
Pedal linkage binding or a defective hydroboost unit
will cause this to happen.
Excessive noise originating in the hydroboost unit
is an indication of the following problems: low power
steering fluid, air in the power steering fluid, a loose
power steering belt, or a restriction in the hydraulic
The interchanging of parts between
hydroboost units of different makes of CESE is
not recommended. Tolerances of parts and
pressure differentials may be different, causing
a jerry-rigged hydroboost unit to exceed the
normal 1,400 psi accumulator pressure.
INJURY TO PERSONNEL AND DAMAGE
TO THE VEHICLE COULD BE THE
RESULT. PROTECT YOURSELF. USE THE
MANUFACTURER S SPECIFICATIONS
WHEN YOU WORK ON THESE UNITS.
The manufacturer recommends that this unit not be
rebuilt or overhauled. If the problem is in the booster,
replace the booster.
TROUBLESHOOTING AIR BRAKE
The purpose of air braking systems (fig. 6-10) is
to enable the operator to apply sufficient braking
action to the wheels of larger and heavier trucks and
construction equipment. Considerable force is
available for braking since the operating pressure is
as high as 110 pounds per square inch. More often,
stopping distances will be much greater than those
shown in figure 6-1, primarily because of the
increased weight of the equipment and load. General
information concerning air braking systems can be
found in chapter 10 of the Construction Mechanic
3&2, NAVEDTRA 10644-G1 .
When you are troubleshooting, first make a visual
inspection and check all the obvious things-open air
drain cocks, off-track compressor belt, broken air lines,
and so forth. Next, perform an air buildup test and an air
Figure 6-10.typical air brake system.