I have a small leak in the bottom of my hydro pump, on my dump truck. It's a small leak and I'm not too concerned. But the thing is, I can't for the life of me see where to refill the the hydro fluid. There has to be a place..... right? there is a bolt on the side, (looks similar to a drain on a walk behind engine), could that be it? I'll try to post a pic of it. Am i supposed to be looking for a resovoir of some sort, cuz there ain't one there. this is a picture of it, from underneath. see that bolt sticking out? is that the hydro fluid refill?