20
MAINTENANCE
Maintenance Procedures
Fifth Wheel Plate and Kingpin Inspection and Lu-
brication
Inspect the kingpin throat for signs of wear. Replace
the kingpin if worn 1/8 inch (3.18 mm) undersize (see
figure 5).
If the grease remaining on the fifth wheel plate con-
tains sand and dirt, clean it before lubricating. The king-
pin and the fifth wheel plate should be greased thor-
oughly with multipurpose grease before connecting the
tractor and trailer.
Frame Inspection
An important phase of trailer maintenance is the in-
spection and repair, if required, of all structural mem-
bers of the trailer frame. The frame must be one solid
unit to carry the load. This also helps prevent major
repair costs and trailer downtime.
Complete frame inspection is required for various
reasons. Trailers are subjected to considerable abuse
due to heavy loads and difficult road conditions under
which they are operated. A trailer loaded to the maxi-
mum rated capacity and pulled at the highest rated
speeds for long periods of time, could develop struc-
tural damage faster than a trailer carrying lighter loads
at lower speeds. Rough use and poor maintenance will
shorten the life of the trailer.
Check the trailer frame daily for cracked structure,
cracked welds, and broken, damaged or lost parts. Struc-
tural cracks will usually show best when the trailer is
loaded. Failures are the result of metal fatigue caused
by flexing and vibration. They will appear as cracks in
the steel frame members. If repairs are needed Do Not
operate the unit until the repairs are made. Structural
repairs must be done by persons experienced in this
field.
NOTE: Failure to maintain decking in good condi-
tion may cause damage to crossmembers.
Weld Repairs
Minor repairs to crossmembers, floorplates, and other
parts which are not part of a main structural member,
may be repaired without special instruction if good
welding practices are followed.
WARNING
Repairs to major structural members must be
made according to the requirements of the part
being repaired. Care must be taken to ensure
that the repairs do not contain stress
concentrations which could lead to another
failure. Repair of T-1 steel especially requires
additional care.
Table 3 lists the recommended electrodes for the
various steels used in Etnyre trailers.
Wheel Bearings
The oil level must be maintained between the "add"
and "full" lines on the hub cap windows (see figure
13). Check for cracked windows, missing vent plugs
and for oil leaks around the hub cap. Oil can be added
through either the vent plug or the filler plug. Clean
and inspect the bearings and change the oil at 50,000
miles or at brake relinings.
Table 3. Electrodes for Weld Repairs.
Type of Steel
Position of Work
AWS
Usual Size
Electrode
Carbon and High Strength
Vertical, Overhead & Flat
E6013
3/16"
Position
E7014
E7018*
T1 Alloy
Vertical, Overhead & Flat
E7018*
3/16
Position
E8018*
E11018*
*Low Hydrogen