June 2018 | VehicleServicePros.com 27
Lubricants should be specifi ed for use on
Oil (synthetic or mineral) – must meet SAE
J2360 requirements or API GL-5/MT-1 guidelines.
Example lubricant weights, per Stemco,
include 75W-90, 80W-90; 80W-140, 85W-140.
Grease (semi-fl uid) – Th e minimum operating
temperature range should be within -20 degrees
F to 325 degrees F.
When considering lubricants
for manually adjusted wheelends,
either synthetic- or petroleum
based oils or greases are
acceptable to use. First, note if
the wheel-end is part of a driven
or non-driven hub assembly.
Diff erent non-driven wheelends
include steer, dolly, trailer,
pusher and tag axles. According
to TMC’s RP 631, fl eets can lubricate
with their preference of oil or
grease. For drive axles, however,
only oil is recommended.
Diff erences in lubrication
types and performance standards
for axles mean diff erent
suggestions for maintenance
(see sidebar “Pre- and post-trip
checklist for wheel-ends”).
Service interval ranges from
100,000 miles to fi ve years in
over-the-road service, depending
on the axle type, manufacturer
and lubricant performance
“Consult with your vehicle,
wheel-end and lubricant
manufacturers to determine
the lubricant that is best for
your particular application,”
ConMet’s Maye advises.
When inspecting lubrication
for wheel-ends, Maye also
says inspection should note
the level and condition of the
It is important to address
improper wheel-end installation,
unit contamination, overloading
or lubrication issues.
Taking into consideration
the integral aspects of identifying
and servicing wheel-end
systems mentioned earlier,
fl eets can be sure to properly
programs to service this area
of the vehicle.
In addition to verifying proper
endplay, fl eets should note
proper wheel nut (including
axle nut, spindle nut, lug nut,
etc.) torque measurements. Whether under- or
over-torqued, improper torqueing accounts for
many wheel-end failures.
Inadequate torque can cause the wheel bearings
to fail – the most common cause of wheelend
failures, says SKF’s Kolany. Th is is due to
the loss of clamping force on the lug nuts, or
amount of pressure applied to keep the wheel
and hub intact.
Conversely, excessive torque can cause additional
stress on components by causing stretching
and fracturing of the lug nut stud.
“If a lug stud is broken or missing, the damaged
lug stud should be replaced along with the two
studs on either side the broken stud,” Kolany says.
“If more than one stud is broken or missing, all
lug studs should be replaced on the hub. Lug nuts
should be cleaned and attached.”
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