Great Dane Champion CP Manuel d'entretien - Page 4

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maintenance 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.

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