The small wheel loader uses a flow amplification steering system, which consists of a priority flow amplification valve and a fully hydraulic steering gear. There are two situations in which the steering direction is heavy. One is that the steering wheel turns heavily, and the other is that the steering wheel turns flexibly, but the whole machine turns heavily.
Heavy steering wheel turning is generally caused by a pilot system failure. Check whether there are problems with the pressure, pipeline connection and pipeline joints of the pilot system.
The steering wheel turns flexibly, but the whole machine turns heavily. It is generally caused by a steering system failure. Check whether there are problems with the pipeline connection, oil suction pipeline, steering system pressure, oil cylinder, etc.
Before measuring and adjusting the system pressure, park the whole machine on a flat ground, lower the boom, level the bucket, turn off the engine, and ensure safety. Before measuring the pilot pressure, put the boom to the lowest position and the bucket to the maximum bucket angle. Before measuring the steering pressure, remove the hydraulic limit rod.
The normal pressure of the pilot is: the engine is not less than 2.2MPa at idle throttle, and not more than 5MPa at high speed throttle.
When measuring the steering pressure, the car must be turned to the maximum angle, in the mechanical limit state, and the steering wheel must be kept in the steering state. When the engine is at high speed throttle, the steering system pressure reaches 15MPa.
If the above two measured pressures do not meet the specified values, they need to be readjusted. Adjusting the pilot pressure is to adjust the overflow valve at the rear of the double pump. Adjusting the steering pressure is at the end of the priority flow amplifier valve.
Check whether the pipeline connection is correct. This situation is mainly old cars. At this time, it is necessary to focus on checking whether the return oil of the pilot pump and the return oil pipeline of the limit valve are connected correctly. If the return oil pipeline is connected incorrectly, it is easy to cause problems such as increased back pressure and heavy operating force. In addition, check whether there is air intake and oil leakage in the oil suction pipeline.
Check whether the pipeline joints are blocked. If the pipeline or joint is blocked by dirt, it is easy to cause problems such as increased back pressure and heavy operating force.
Check whether the oil cylinder has internal leakage, retract the steering oil cylinder piston to the bottom, remove the rodless chamber oil pipe, and continue to fill the rod chamber with oil. If there is a lot of oil leaking out of the rodless chamber oil port, it means that the piston seal ring is damaged and should be replaced. If the oil cylinder leaks, the steering system pressure will generally be low and the steering will be weak.