As for the auxiliary pump on the aluminum extrusion machine without pressure, we need to do a small check on the machine. First, determine whether the steering of the oil pump is correct; second, check the relief valve, check the oil circuit, and see if the relief valve works; finally, check whether there is any problem with the pump itself. If there is nothing abnormal in the inspection and the sound is normal, you can try to remove the overflow valve and clean it with diesel oil, and blow down the holes on the valve with high-pressure air. Pay special attention to the small damping holes, which are easy to block. Try a new one. Wash the old one and put it away for next time use.