Manual

Rubber-Lined Body System. A new
offering available from the factory is the
rubber-lined body system. For impact
resistance in hard-rock applications,
rubber liners offer a practical, durable
and cost-effective solution. They dissipate
impact energy, maximizing body life
and reduce noise, improving job site
work conditions inside and outside the
cab. These maintenance-free liners also
require minimal installation time.
The density of rubber is 20 percent of
the density of steel, yet its ability to
absorb impact is three times that of
steel. This gives rubber a high impact
strength-to-weight ratio. In addition,
truck operators enjoy a better operator
environment, without the hard impacts
felt during loading.
Body System Selection. Two primary
factors affect body selection:
• Impact. Impact is the energy that is
created by the material when it hits the
truck body. The condition and size of
material, combined with the height at
which it is dropped, greatly determines
the impact energy that the body must
absorb. The most measurable effect of
impact is structural bending, chipping,
cracking, and spalling. These conditions
can be created when the impact absorption
capability is exceeded by the impact of
the material itself. Generally speaking, a
high impact material might be basalt or
granite. A medium impact material
might be mixture of decomposed rock
(75 percent rock, 25 percent dirt), while
a low impact material might simply be
dry, packed dirt.
• Abrasion or Wear. The tendency of a
material to grind away the surface of a
body by means of friction is abrasion.
Abrasion occurs when a material’s
hardness is higher than the wear surface
that it slides on. A high abrasion material
could be any rock material containing a
high proportion of hard, angular minerals
such as quartz. Granite tends to be highly
abrasive. A moderate abrasion material
might contain a high proportion of
minerals such as calcite. Limestone is
most likely in the moderately abrasive
category. A low abrasion material could
be any material that contains minerals
such as talc.
Exhaust Routing. There are three exhaust
routing systems available for the 772,
depending on the customer’s requirements
for body heat and sound:
• Full-Time Body Routing. The standard
design provides full-time routing of
exhaust into the body to heat areas where
material gathers. This plays a crucial role
in preventing material from being retained
in the body during dumping. Not for use
with rubber liner body systems.
• Full-Time Muffler Routing. The second
option is the full-time routing of exhaust
through a muffler, which eliminates
exhaust in the body. This option should
be used for rubber-lined bodies or
applications that do not require
body heat.
• Diverter Box Routing. The final
option provides a diverter box so that
the customer has the flexibility to
choose whether to route the exhaust
through the body or directly through
the muffler. Not for use with rubber
liner body systems.
Target Payload Strategy. Your Caterpillar
Dealer can help you manage to target
payload to maximize equipment use,
ensure safe operation, increase
productivity and lower cost-per-ton.
• Underloading increases costs due
to lost payloads, underutilizes
equipment, and increases
cost-per-ton.
• Overloading causes excessive wear on
vehicle components, such as brakes,
tires and drive train, reducing
component life and increasing
maintenance costs and repairs.
Matched Systems. Designed to work as
an optimum pass/match system, the 772
is best sized to match the 988H Wheel
Loader, with a 4 pass/match, the 990H
Wheel Loader with 3 pass/match, and
the 385C Hydraulic Excavator with a
6 pass/match.
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