» Selecting the proper wheel nut can reduce
the potential of catastrophic failure.
Photo from iStock
November/December 2017 | VehicleServicePros.com 29
a unit supported by only a
jack. If the axle is supported
with spring brake chambers,
following the manufacturer’s
instructions, carefully
compress and lock the springs
to completely release the
brake.
Next, using a proper hub
support, remove the spindle
nut, outer bearing (and spacer
if it is a PreSet system) and
pull the hub assembly off the
spindle. It is recommended to
check for the following when
inspecting a spindle and hub:
Spindle and spindle
threads: Inspect the spindle
and spindle threads for
damage, and remove light fret.
Also check for spalling
(wearing away of the surface),
corrosion pits, discoloration
from overheating, punch
marks/chisel marks, weld
beads and upset metal. It is
important to note damaged
threads can be repaired using
a pitch thread fi le or die nut.
Fastener, lock nut and
bearing adjustment nut and
washer: Th e use of these spindle
end components varies by
truck or trailer manufacturer.
Inspect the fastener, lock
nut, bearing adjustment nut
and washer. Look for chisel
marks or other deformations
as a sign of improper installation,
or an attempt to make
temporary repairs.
Bearing inspection: Inspect
bearings for pitting, rust
or corrosion and spalling.
Replace the bearings if any of
these conditions exist.
Seal inspection: When
idle for an extended period
of time, the upper half of the
seal and bearing do not have
contact with the lubricant.
Seal rubber will dry out and
become stiff , losing its ability
to seal. Always replace the
seals before putting a vehicle
back in service.
Lubricant inspection:
Inspect lubricant for the
presence of hard particle
contaminants and water
contaminants (e.g. milky appearance or discoloration).
Th oroughly clean the hub and spindle
and inspect for signs of corrosion. Be sure to
service the hub as needed, including the replace-
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