Open the cover on the RHS. of the machine at the front of the cab. The hydraulic oil filter is inside. You should see the filler on top of the filter - a short piece of large bore hose with a hexagonal plug in the top.
Do not have the engine running, or start up when the plug is removed (oil will shoot out!)
There is a better tool to undo the ram end caps. A large "C" spanner, or even plummer's chain wrench, with a peg inserted into the hole in the side of the cap to prevent the chain skidding round.
Mr. Toad
March 2009