AC5050 info

There are two holes on either side of the rear lift fluid drain plug.Each hole has what appears to be the ends of cotter keys sticking out.I have lift fluid dripping out of one of these holes.Can anyone tell me what these holes are for and what maybe causing my fluid leak here.I've been unable to find any reference to these on the parts break down or user manuals I have,any help would be appreciated.Foxyboy