Crane turned to heavy investigation

1 Check the hydraulic oil quality
If the hydraulic oil deterioration, the gap will steering pump leakage increases, in turn cause the system pressure is low. Open the fuel tank inspection, normal quality hydraulic oil, oil is plentiful.
2 Check the steering valve with steering cylinder
If the steering valve sticking, its performance should be turned to the heavy side, the other side turn to normal. Steering axle with the  jib crane  outrigger top up, check clearances and slide steering valve spool volume is normal, indicating steering valve trouble.
Still steering axle jacking state inspection steering cylinder position, and found a good appearance of the hydraulic cylinder, and the active state and the normal stroke volume, thereby indicating that the hydraulic cylinder intact.
3 Check the steering pump
Start the engine, steering pump flowlines touch vibration sense, which illustrate the tubing pressure oil flow steering pump is working properly.
4 detection system pressure
Maximum speed of the engine does not turn the steering wheel, the system pressure should be 2.8 ~ 3.2MPa, the engine idling state, the system pressure should be 2.0 ~ 2.1MPa. The results do not turn the steering wheel, the engine idling, the measured system pressure is only 1.2MPa,gantry crane the maximum engine speed when the system pressure is reduced to 1.0MPa, significantly lower than the nominal steering pressure 2.8MPa. This preliminary determination is due to the heavy steering steering system pressure is insufficient. The reason may be turning vent valve, check valve worn or faulty steering pump.
After further analysis: the crane is not running, the steering valve is also no action under the premise of improving the speed of the engine throttle, the system pressure is lower than the idle state, should turn to vent valve, check valve wear nothing is likely to be caused by poor steering pump oil into the.
5 Overhauling filters
The aircraft steering hydraulic tank from the tank 1, the oil filter 2, a spring retainer 3, spring 4, spacer 5, filter plate 6, the fuel tank cap 7, into the oil filter 8, bolts 9 and other components,bridge gantry crane such as shown in the drawings.
Remove the oil filter 2 will come out and found it to be blocked by dirt. The oil filter 2 retest thoroughly cleaned after loading machine, the fault disappears.