For oil leakage issues, first check whether the oil level in the sight window exceeds the MAX mark, and tighten the oil pump cap screws to a torque of 1.5 N·m. If there is oil seepage in the lubrication system, disassemble the feed dog base assembly, clean any residual lint with industrial alcohol, and replace aged O-rings. If oil is leaking from the main shaft bearing, it is recommended to refill the bearing housing with high-temperature-resistant grease, keeping the filling volume at about two-thirds of the cavity capacity.
Abnormal operating noise typically originates from issues in the transmission system and can be diagnosed using a three-step method: first, check the tension of the timing belt (standard deflection is 5–7 mm); second, inspect the clearance between the rotary hook and feed dog (recommended gap is 0.05–0.1 mm); and finally, measure the noise level using a decibel meter at a distance of 30 cm from the machine. If the noise consistently exceeds 65 dB, inspect the motor bearings for wear. For periodic metallic friction sounds, focus on the contact surface between the needle plate positioning pin and the rotary hook housing for possible burrs.