OM3070 Operation - Section 30 Operating Instructions Page 30-7 EMERGENCY STEERING SYSTEM 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. 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. 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. 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. 4.
Turn the key switch to the ON position, but DO NOT start the engine. a. Steering system pressure: Verify that the low steering pressure warning light is illuminated. If it is not illuminated, immediately notify maintenance personnel. DO NOT operate the truck until the problem is corrected. 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. b. Steering accumulator precharge: Verify that the low accumulator precharge warning light is not illuminated and the warning buzzer is not sounding.
If the warning light is illuminated and the buzzer is sounding, immediately notify maintenance personnel. DO NOT operate the truck until the problem is corrected. 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. 5. Start the engine and allow the steering accumulators to fully charge. Turn the steering wheel so that the front wheels are straight. 6. Check the hydraulic tank oil level while the engine is on. a.
If the oil level is visible in center of the lower sight glass and does not cover the entire lower sight glass, the steering accumulators are adequately charged. Proceed to Step 7. Ensure no one is near the front tires during this test. All personnel are warned that the clearances change when the truck is steered and this could cause serious injury. b. If the oil level is below the lower sight glass, the steering accumulators are not ade- quately charged. Stop the engine and turn the key switch to the OFF position. Immedi- ately notify maintenance personnel. DO NOT operate the truck until the problem is cor- rected. This test can only be performed with an empty truck. 1.
Park the empty truck on flat, level ground. Lower the dump body onto the frame and stop the engine. Ensure the key switch is in the OFF position.