Great Dane Champion CP Руководство по техническому обслуживанию - Страница 4
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Печатать страницуmaintenance tips
BREAKING-IN A NEW TRAILER
The most critical time in a new trailer's life is its initial
in-service check and first month's "shakedown."
Preventive maintenance mechanics should be alert for
under-inflated tires and threaded fasteners that may
have loosened from factory-torque settings. Fastener
torque should be all-inclusive and include refrigeration
units, tanks, steps, carriers etc.
Following are several areas that deserve particularly
close attention during the first 30 days of a van or
platform trailer's service life. Of course, your
operation's maintenance records should reflect all areas
which need to be closely checked.
TIRES
While a new trailer's tires were correctly inflated when
they were mounted at the factory, tire pressure is
related to ambient temperature at inflation time. If a new
trailer had tires mounted in a 70˚ F. ambient
environment, but was put in service in 20˚ F. weather,
the tires may have lost as much as 10 psi for every drop
of 20˚ F. in ambient temperatures below 50˚ F. Therefore,
all tire pressures should be verified with an air gauge,
and rechecked each time the tractor refuels.
WHEELS
Smaller fleets commonly overlook the need to retighten
new-trailer-wheel lug nuts after the first 50 to 100 mi. of
service on the initial "in-service." Retightening
compensates for "normal" clamp force lost due to
"seating in" of new materials. Tests have shown
new-trailer-wheel lug nuts lose 250 lb-ft, or about half of
their original torque value, during a short period of initial
service. Unless those nuts are retightened to spec,
additional clamping force will be lost, and
damage to components will occur. Re-tightening during
the initial in-service prevents wheel and stud damage.
Thereafter, lug nuts should be checked every 25,000 mi.
LEAF-SPRING SUSPENSIONS
All tandem axles are aligned when new trailers leave the
factory. However, suspension fasteners may sometimes
loosen, possibly causing alignment settings to change,
and that can translate into possible erratic ride, or
accelerated tire wear. Therefore, at the first TPM
interval, all suspension-system fasteners should be
rechecked for correct torque value.
When tightening suspension-system fasteners,
mechanics must tighten the "nut side" of torque-arm
bolts. Tightening bolt heads does not produce the
correct clamping force on the fastener.
It is also important to keep U-bolts, as well as torque-
arm bolts, tight. Loose U-bolts allow trailer axles to
shift, and even minor shifting during braking can cause
control problems, excessive tire wear, or even broken
spring leaves.
When U-bolts are torqued to proper specs, leaf-spring
main leaves remain in proper contact with wear pads,
with no "twists." Spring wear-pad contact will then be
even, too.
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Also, at the first TPM, a trailer mechanic should take the
time to verify that there are no obstructions to move-
ment of the suspension equalizers.
When the mechanic has made sure all fasteners are
tight, he should use the 50-ft.-tape method, with axle
extenders, to verify that the trailer tandem is, indeed,
properly aligned. Remember: the longer the trailer,
the more critical tandem alignment is to long tire life.
AIR-SPRING SUSPENSIONS
Loose U-bolts in an air-spring suspension can cause a
new trailer to roll and sway. Usually, a driver is quick
to report this condition. The mechanic should make
doubly sure that trailer-suspension fasteners, including
U-bolts, are properly tightened.
Excessive play in an air-spring suspension's front-pivot
connection is another cause of premature tire wear and
erratic handing. Again, connection bolts, which may
have loosened during the first weeks of service, may
produce such handling problems. If not retightened,
these loose bolts can cause rubber bushing wear.
SLIDING-TANDEM OPERATION
A driver learning to handle a new trailer equipped with a
sliding tandem should be sure he knows exactly how to
use the stop-selector bar. He should also make sure
that all four slider lock pins are set in place before
operating the trailer, otherwise the tandem may not be
"locked," and a sudden brake application could force
the slider rearward, causing damage to the tandem
and trailer.
AIR SYSTEM AND BRAKE OPERATION
During the first month's operation, a certain amount
of "burnishing in" of brake lining occurs. This is normal
and may result in some adjustment loss. Because
out-of-adjustment trailer brakes mean increased stop-
ping distance, plus an increased potential for jackknif-
ing under certain conditions, trailer brake adjustment
should be checked at the first TPM inspection.
During routine maintenance the dust cover cap on air
chambers must be inspected to assure that is in place
and sealing properly.
ANNUAL FHWA INSPECTION
It is the carriers' responsibility to make sure that the
vehicles operated by them are inspected and main-
tained under this Federal requirement. During this
inspection, make sure the upper slide rail to crossmem-
ber welds, pintle hook assemblies, safety equipment,
etc. are inspected and corrected as required.
DOORS
Almost invariably, a new trailer's hinged-type doors
are difficult to latch. Drivers should expect to use extra
muscle to secure doors until seals seat, but drivers
should not use bars or some other device to force
doors shut. It is equally important not to make adjust-
ments to a new trailer's door latches or hinges to
"correct" door closing. This will result in a poor sealing
later on.
appearance maintenance
Appearance maintenance includes cleaning, polishing,
corrosion prevention and removal, and protective
coatings. You must have a working knowledge of each
for the complete and proper appearance maintenance
of a Great Dane trailer.
WASHING AND CHEMICALS
Improper use of chemical cleaners has caused many
a newly delivered trailer's finish to streak and fade,
particularly yellow, red and black models. Ironically,
fade is often caused by a desire to keep the units
clean—and using too strong a chemical solution. When
instructions call for a 150:1 water/chemical ratio, do not
use a 50:1 ratio. Sometimes fading caused by an overly
concentrated caustic agent may be remedied with
warm water rinsing and application of a glazing wax.
APPEARANCE MAINTENANCE MATERIALS
Many chemical companies compound materials for
appearance maintenance, and most provide instructions.
Protective films, such as paints and clear coats, are
necessary for the prevention of corrosion and the
preservation of metal and wood surfaces. They add
color, beauty, and distinction.
freezing weather maintenance
Winter cold weather and its slush, sleet, and snow pres-
ent special problems to the truck trailer operator and to
maintenance men. Low temperatures can mean frozen
and sluggish or inoperative brakes, sagging light and
brake lines, broken connections, increased corrosion,
and can require the installation of winter equipment.
Enclosed air systems for brakes and air-operated
equipment should be drained regularly of accumulated
moisture. The air tanks should be drained daily. The
trailer air system should be treated through tractor
equipment only. Use of additives can cause damage to
the brake system. This could result in metal corrosion or
swelling of brake valve seals. Make sure electrical and
brake lines are adequately supported.
Ice and mud accumulations on brake lines and actua-
tors should be removed regularly. Any air leaks that may
exist are difficult to find when they are encased in ice
and mud.
warning
Do not use heat on any part of the air system.
The use of heat can cause a rupture and can be
very dangerous.
WINTER CORROSION MAINTENANCE
Magnesium and calcium chlorides used to control snow
and ice on many highways, if not property cleaned from
your tractor and trailer equipment after each trip, will
result in rust and corrosion damage in as little as one
winter of operation.
Information concerning corrosion maintenance can be
found in the publication's bibliography and on Great
Dane's website, www.greatdanetrailers.com.
NOTICE:
Aluminum brighteners should not be used.
Trailer undercoat materials can lose effectiveness if
steam cleaned or if they come in contact with most
solvents.
The underside, including beams, has been undercoated
with a special, soft, rust preventive coating. To prolong
the life of this coating, avoid the use of high-pressure
washers, strong cleaning solutions and brighteners.
Due to the normal weathering and abrasion caused
by road conditions this coating must be inspected and
recoated as necessary (approximately every 24 months).
Dry-freight laminated wood floors should be cleaned
by sweeping and should not be washed out.
BENEFITS OF APPEARANCE MAINTENANCE
Complete and proper appearance maintenance of
Great Dane trailers not only adds to their physical
condition and ultimate trade-in value but also favorably
affects the operator's feelings about himself and his
company. It also favorably affects the public image
of the company.
These references outline:
1. What states use these chemicals
2. How these chemicals affect equipment operated
over road surfaces treated with it.
3. What you should do to protect and maintain your
equipment when it's exposed to these highly
corrosive chemicals.
SUGGESTED PREVENTIVE MAINTENANCE
EVERY 1,000 MILES:
Check oil level in wheel hub and inspect wheel
hub for leaks
15,000 MILES OR MINIMUM OF TWICE A YEAR:
Check brake adjustment
Check and repack wheel bearings as required once
per year or every 100,000 miles as recommended
by the T.M.C.
25,000 to 30,000 MILES:
Check lining wear and estimate reline time
Inspect camshaft, camshaft spider bushing and
camshaft support bracket bushing for any signs
of wear
Lubricate brake actuating components
100,000 MILES, ONCE A YEAR, OR AT BRAKE
RELINE:
Replace wheel bearing lubricating oil (if applicable)
Check brake air actuators and adjusters
Inspect brake rollers, roller shafts, anchor pins and
bushings and replace if necessary
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