Oil cooler hose leaking

as title says i developed a leak on the upper braided hose that goes fro. reservoir to cooler. Has this happened before? can it possibly need just to be tightened? Its such a pain in the butt to get a 36in spanner on that connection. The friggin water pipe is in the way and of course its not the easy one to take out.
My question is can the reservoir be removed without pulling engine? becsuse i dont think i have enough room to get a wrench on the pipe going to sidd. possibly if i remove fuel tank. any thoughts?