Komatsu 930E-2, Shop Manual

Page: 41 / 739

the service brakes. Releasing the pedal returns the
brake and retarder to the “off” position.
When the pedal is partially depressed, the dynamic
retarding is actuated. As the pedal is further depressed
to where dynamic retarding is fully applied; the service
brakes (while maintaining full retarding) are then actu-
ated through a hydraulic valve, which modulates pres-
sure to the service brakes. Completely depressing
the pedal causes full application of both dynamic
retarding AND the service brakes. An indicator light
in the overhead panel will illuminate, and an increase
in pedal resistance, will be felt when the the Service
Brakes are applied.
For normal truck operation, Dynamic Retarding (lever
or foot-operated pedal) should be used to slow and
control the speed of the truck.
Service brakes should be applied only when dynamic
retarding requires additional braking force to slow the
truck speed quickly, or when bringing the truck to a
COMPLETE stop.
STARTING ON A GRADE WITH A
LOADED TRUCK
Initial propulsion with a loaded truck should begin from
a level surface whenever possible, but when there are
circumstances where the starting on a hill or grade
cannot be avoided, use the following procedure:
1. Fully depress the foot-operated retarder/service
brake pedal (do NOT use retarder lever) to hold
the truck on the grade. With service brakes fully
applied, move the selector switch to a drive posi-
tion (Forward/Reverse) and increase engine
RPM with throttle pedal.
2. As engine RPM approaches maximum, and op-
erator senses propulsion effort working against
the brakes, release the brakes and let truck move-
ment start. Be sure to completely release the
foot-operated retarder/service brake pedal. As
truck speed increases above 3-5 MPH (5-8 KPH)
the Propulsion System Control (PSC)will drop
propulsion, if the retarder is still applied.
Releasing and reapplying dynamic retarding dur-
ing a hill start operation will result in loss of
propulsion.
PASSING
1. Do not pass another truck on a hill or blind curve!
2. Before passing, make sure the road ahead is
clear. If a disabled truck is blocking your lane,
slow down and pass with extreme caution.
3. Use only the areas designated for passing.
LOADING
1. Pull into the loading area with caution. Remain at
a safe distance while truck ahead is being loaded.
2. Do not drive over unprotected power cables.
3. When approaching or leaving a loading area,
watch out for other vehicles and for personnel
working in the area.
4. When pulling in under a loader or shovel, follow
“Spotter” or “Shovel Operator” signals. The truck
operator may speed up loading operations by
observing the location and loading cycle of the
truck being loaded ahead, then follow a similar
pattern.
5. When being loaded, operator should stay in truck
cab with engine running.
Place Selector Switch in “Neutral” and apply
Wheel Brake Lock.
6. When loaded, pull away from shovel as quickly as
possible but with extreme caution.
DUMPING
1. Pull into dump area with extreme caution. Make
sure area is clear of persons and obstructions,
including overhead utility lines. Obey signals di-
rected by the spotter, if present.
Avoid unstable areas. Stay a safe distance from
edge of dump area.
Position truck on a solid, level surface before
dumping.
As body raises, the truck Center of Gravity (CG)
will move. Truck must be on level surface to pre-
vent tipping / rolling!
A03017 General Safety and Operating Instructions A3-27