Components
Each component has individual measure-
ment techniques, wear limits, wear charts,
rebuildability criteria, wear patterns and
structural problems. The general informa-
tion for each component is covered in the
following section. Specific additions and
exceptions are covered in the individual
product sections.
Percent Worn Charts
The percent worn charts section of this
handbook translate direct component
measurements into percent worn for
Caterpillar parts only.
Remember — all percent worn figures
shown are percent of time used and not
percent of material used. This allows them
to be used to directly calculate or project
total potential time (or life left) to the
service limit. These charts consider the
slower rate of wear when the hardened
case is still there and the faster rate of
wear that occurs when softer material is
exposed. In some cases they also take into
account different expected wear rates after
the service limit. In most cases they are
not “straight-line” relationships.
Charts are provided for high and low impact
applications where applicable. Measure-
ments corresponding to 100 percent worn
(the service limit) are underlined.
In most cases, service limit projections
made from less than 30 percent worn can
not be considered accurate. However, such
projections can be used to determine call
back dates for remeasuring.
Percentages above 100 percent have been
provided so projections to 120 percent
worn can be calculated. Backward projec-
tions to service limit (100 percent) can
also be made to determine when the
service limit was reached. The extent of
percentages shown beyond 100 percent
has no particular significance.
Guidance for the selection of high, moderate
or low impact and lesser or greater allow-
able wear charts is provided at the front of
each section of wear charts.
A separate discussion under each component
sub-section (links, bushings, etc.) describes
how the service limit was derived and the
risk involved when the component is worn
past that point.
NOTE: Competitive undercarriage inspec-
tion, wear life and maintenance/rebuild
projection cannot be determined from
information contained in the handbook
because of a lack of information about
design, expected wear rates and service
limits even when some important dimen-
sions are similar.
27
General Information
PERCENT WORN CHARTS