I recently bought a bobcat 442 excavator and I am slowly fixing all the bugs/issues with it. When we bought the machine the hydraulic filter restriction light was on. We replaced the filter and the hydraulic fluid with factory filter and oil and the light is still on. We have run the machine a little and the light stays on. I am assuming it must be a bad sensor. My question is if this light is on does that mean the filter is being bypassed?
Not necessarily, the sensor measures the pressure difference between inlet and outlet of the filter and typically comes on at least 5 psi lower than the opening pressure of the bypass check in the filter head. The two are not connected so if you have a faulty sensor it's just that to replace.