I have an old JCB loadall and I am changing all the oils and filters. The manual says to also clean the hydraulic suction strainer. Can this simply be removed from the side of the tank by unbolting the cover plate or does the oil need to be drained first? The strainer is on the side of the tank and so it cannot be lifted upwards out of the tank like the hydraulic filter which can be done with a full tank of oil?