Good day , can anyone tell me how they top up their hydraulic oil on a Kubota KX 030-4 excavator , when I take off the breather filter where I assume I would be pouring the oil in it is blocked by some kind of plastic plate underneath, there is no filling hole on tope of the tank , do I have to take the whole 6" cover underneath which in their manual they call : cover of the return filter with filter support , seems like an odd thing to do . Thanks in advance for any advice . Cheers