Emergency Steering System; Operation; Pre-Operation Testing - Komatsu 930E-4SE Operation & Maintenance Manual

Operating Instructions - Section 30
Page 30-10
Retard System Test
1. Place the directional control lever in the PARK
position.
2. Press the brake test switch and wait for the
brake check light to be on solid.
3. The DID panel will display:
Parking Brake or Retard Test READY
Press Accel or Retard Pedal to Start
4. Fully depress the retard pedal. The drive sys-
tem controller will ramp up the engine speed,
close RP1, close RP2, close RP3 (if present),
turn on the choppers, and test the retarding sys-
tem. The system will verify current flow through
each grid leg and the grid blower motor.
5. The DID panel will display the current status of
the test.
Retard System Test ACTIVE
RP1 RP2 RP3 CHOP
(Elements are added as the test progresses.)
6. Upon successful completion of the test, the light
will flash for 10 seconds indicating a successful
test. The DID panel will display:
Retard System Test PASSED
or
Retard System Test FAILED or Incomplete
NOTE: If the brake check light never flashes, but
turns off, the test has failed.
If the truck fails the retard system test, notify
maintenance personnel immediately. Do not
resume operation unless the truck passes all
brake tests.
7. When the operator releases the retard pedal,
the test will stop and the brake check light will
turn off.
8. If the retard system failed the test, notify main-
tenance personnel immediately. Do not resume
operation unless the truck passes all brake
tests.

EMERGENCY STEERING SYSTEM

Operation

This truck is equipped with an emergency steering
system. This system is a backup in the event of loss
of oil supply to the main steering system. The
emergency steering system was designed to meet or
exceed SAE J1511 and ISO 5010 standards.
If the low steering system pressure indicator light and
alarm are activated, a failure in the hydraulic oil
supply to the steering and brake system exists. When
the alarm is activated, typically there is enough
hydraulic pressure stored in the brake and steering
accumulators to allow brief operation of the steering
and brake functions. However, this oil supply is
limited. Therefore, it is important to stop the truck as
quickly and safely as possible after the alarm is first
activated.
If the oil supply pressure drops to a predetermined
level, the low brake pressure warning light will also
illuminate. If the oil pressure continues to decrease,
the brake auto-apply feature will activate the service
brakes to stop the truck.

Pre-Operation Testing

NOTE: Komatsu recommends that operators perform
this test to verify that the steering accumulator
precharge pressure is adequate at the beginning of
each shift before operating the truck.
1. Park the empty truck on flat, level ground.
Lower the dump body onto the frame and stop
the engine. Make sure that the key switch is in
the OFF position.
2. Wait at least 90 seconds to verify that all
hydraulic pressure has been relieved from the
steering accumulators. Turn the steering wheel
from stop to stop. If the front wheels do not
move, there is no hydraulic pressure.
3. Check the hydraulic tank oil level. The oil level
must be visible in the center of the upper sight
glass and must not cover the entire upper sight
glass. Add oil if necessary. Do not overfill.
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