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Upon completion of dumping, the valve is shifted into “LOWER” until the dump body is returned to
the transit position. Finally, the valve is shifted into “HOLD” and the power take-off is disengaged.
Serious damage to the pump could occur if the power take-off (PTO) remains in gear while
operating the truck. Do not operate the PTO while the truck is in gear unless the PTO is used in
spreading the load.
While the body is in dump position, do not leave the controls. Keep the body in sight. Be alert to
stop or lower the body instantly.
9.7.4
IN TRANSIT
Do not operate a dump trailer IN TRANSIT with the body slightly raised, the cylinder pressurized,
and the valve in “Hold”. The use of the cylinder as a shock absorber may lead to failure of the
cylinder and/or its mounting parts.
9.7.5
HYDRAULIC HOSES
Hydraulic hoses should be maintained in good condition. A worn or damaged hose may blow out
while the dump body is being raised.
9.8 TIP-OVER
CONDITIONS
9.8.1
WIND
Do not attempt dumping operations in unsafe wind conditions. This could cause a tip-over.
9.8.2
TERRAIN
The body should be raised only when both the tractor and the trailer wheels are on smooth, level,
compacted surfaces. Lower the body immediately if leaning is detected.
9.8.3
HUNG LOADS
A hung load is a commodity that does not discharge when a dump body is raised to an elevated
position. To avoid a tip-over due to a hung load, the driver should be warned by an observer of this
condition and immediately lower the dump body.
9.8.4
JACKKNIFE
A jackknife position of the tractor with the trailer is dangerous when dumping. With a frame type end
dump in a jackknifed condition, the upper coupler pivots on bearings, contributing nothing to the
dump stability. When the tractor and trailer are straight, the coupler bearings are apart, assisting in
stabilizing the unit. When a frameless end dump trailer is coupled to a tractor fifth wheel, the fifth
wheel must be “blocked”. Blocking restricts pivoting of the fifth wheel plate and draft arms. Lift the
dump body only when the tractor and trailer are in a straight line. If a loaded trailer does start to
lean while jackknifed, releasing the tractor brakes and rolling ahead may actually assist in tipping
the trailer. However, if dumping in a straight line, releasing the tractor brakes and rolling ahead may
prevent a tip-over.
9.8.5
TIRES
A blown tire or severely under inflated tire can cause instability when dumping. Always check tires
visually for cuts or punctures. Make sure all tires are properly inflated.
9.8.6
HUMPING
Humping is a rapid acceleration/deceleration method used to loosen a hung load from a trailer. If
MAKE SURE POWER TAKE-OFF CONTROLS ARE EITHE
R
COMPLETELY ENGAGED OR DISENGAGED.