Wear and Structural Problems
on Sealed or Dry Track Pins
Internal Wear (Pin O.D. Wear and
Bushing I.D. Wear)
CAUSES: Rotational contact with abrasive
and/or I.D. of bushings.
ACCELERATORS: Horsepower, weight
and speed of machine; abrasiveness, loss
of sealing effect and snakiness, impact,
terrain packing loads, and maneuvering.
Track tension, too wide shoes, worn rear
rollers and high speed non-productive
work are main controllable variables.
EFFECT: Track pitch increase with result-
ing mismatch (see sprocket wear patterns).
Beginning of “chain-reaction” of most
advanced undercarriage component wear.
REMEDIES: Eliminate or reduce control-
lable accelerator variables, turn Sealed
Track pins and bushings at service limit.
Use Sealed and Lubricated Track.
Pin End Wear
CAUSES: Sliding contact with guiding
and/or roller guards plus abrasives (may
be seen at either or both ends of pin —
usually more severe on outboard side).
ACCELERATORS: Uneven terrain, and
side hill operation. Too-wide shoes, worn
rolling component flange misalignment
and snaky track are main controllable
variables.
EFFECT: Pin will have to be re-cham-
fered before re-assembling track at turn
time to avoid broaching link pin bore
with sharp edges resulting in pin retention
loss. Extreme cases will show wear on
outer face of pin boss which reduces pin
retention.
REMEDIES: Eliminate or reduce control-
lable accelerator variables, particularly
snaky track by turning pins and bushings.
Pin Loosening
CAUSES: Loss of press fit retention in
link pin bore.
ACCELERATORS: (1) Severe repeated
impact yields or cracks link bore. (2)
Uneven terrain and too-wide shoes
increase flexing of pin in bores. (3) Link
bore broached by improper track press
alignment at reassembly time. (4) Loose
track shoes.
EFFECT: Loss of pin and separation of
track; loss of parts reusability and rebuild-
ability.
REMEDIES: (1) Eliminate or reduce con-
trollable variables which increase impact
loads and flexing of joint such as too-wide
shoes. (2) Control track press alignment
capability and re-chamfer worn pin ends
to reduce bore broaching.
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General Information
SEALED TRACK PINS & BUSHINGS