Emergency Steering System - Komatsu 730E Operation & Maintenance Manual

Operation - Section 30
Page 30-12

EMERGENCY STEERING SYSTEM

Operation
The 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 emer-
gency 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 sup-
ply to the steering and brake system exists. When the
alarm is activated, typically there is enough hydraulic
pressure stored in the brake and steering accumula-
tors to allow brief operation of the steering and brake
functions. However, this oil supply is limited. There-
fore, 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 and the ser-
vice brakes will apply automatically to stop the truck.
Testing
This test can only be performed with an empty truck.
1. Ensure no one is near the front tires during this
test. Use a spotter to keep the area around the
front tires clear of personnel during this test.
2. Start the engine. Allow the hydraulic system to
reach full pressure and the accumulators to fill
with oil.
3. Shut the engine off by using the engine stop
button located on the center console. DO NOT
turn the key switch OFF.
4. Turn the steering wheel.
a. If the front tires respond when the steering
wheel is turned, the emergency steering sys-
tem is functioning properly. Turn the key
switch OFF.
b. If the front tires do not steer, turn the key
switch OFF and notify maintenance person-
nel immediately. DO NOT drive the truck
until the problem has been repaired and the
truck can pass this test.
If the truck passes this test, the emergency steering
system is functioning properly.
OM3043 06/06
Operating Instructions