CAUTION
Retread tires are not authorized for use on the M747 semitrailer.
3
LIGHTS
0.2
Operate lights. Replace burned-out lamps. Note condition of reflectors. Check
utility electrical outlets for proper operation. Check operation of retractable
clearance lights in all positions.
0.3
4
LEAKS
Look under semitrailer for an indication of grease. Inspect for air leaks.
0.3
AIR SUSPENSION SYSTEM
5
With semitrailer connected to towing vehicles and air pressure applied, check air
bags for operation and evidence of leaks. Raise and lower rear axles, noting
operation. Check for evidence of damage or wear. Apply air gage to regulator
valve air valves and check for correct pressure (para 4-37c). Adjust regulator
valves if required (para 4-37c). Check for wear at lower lift rod connections.
Replace missing cotter pins. Check shock absorbers for oil leaks. Replace if leak
is found (pare 4-56 and 4-57). Check rubber axle stops for damage or wear and
replace if necessary (para 4-58). Check security of air bag protection plates.
0.3
BRAKES
With semitrailer air lines connected towing vehicle air supply, apply air gage
to air valve on auxiliary air supply valve and check system pressure (minimum
65 psi required]. Open, inspect and clean an air chamber. If dirt is present, clean
0.2
7
TRAILER EQUIPMENT
Visually inspect semitrailer towing connections and winching equipment (fig. 2-
0.4
8
Check condition and operation of landing gear and ramps. Inspect for damage,
wear or cracks in metal. Replace damaged parts (pare 4-63 and 4-65).
0.4
FRAME ASSEMBLY AND GOOSENECK
9
Inspect for damaged or broken parts. Check kingpin for damage or wear. Re-
place the kingpin if it has uneven wear of 1/16 inch over 1/4 of the circumfer-
ence of pin, even wear of 1/16 inch over all the circumference of pin, crack of
any size on pin welds, or a nick, chip or gouge deeper than 1/8 inch anywhere on
the surface of pin. Note condition of paint and legibility of markings and data
plates. Inspect for frame cracks where walking beam saddle bracket attaches to
main frame. Inspect for frame cracks on main frame where bowtie crossmember
joins main frame, near walking beam suspension, (No. 1-200 only).
DURING ROAD TEST
Man-hours required: 0.4
0.1
UNUSUAL NOISE
At all times during road test, be alert for unusual or excessive noises that may
indicate damage, looseness, defects, or deficient lubrication in semitrailer
components and wheels.
0.3
BRAKES
Make several stops, noting side pull, noise, chatter, or any other unusual
condition. Apply semitrailer-brakes alone and observe if they operate effectively.
Disconnect hoses from towing vehicle and see if semitrailer brakes apply.
Change 2
4-7