The hydro filter on a Massey Ferguson 1020 should be located on the side, near the back of the tractor, on the left-hand side. This filter is usually enclosed in a black plastic housing and is easily accessible. It is important for the filter to be changed regularly to prevent slowing down the engine or power of the tractor. If a clogged filter is not replaced, it could affect the performance of the tractor and cause other issues.