I hate those combines, should have burnt them all of the get go. In regards to the leak the thing to do is replace the steel lines with rubber. There's a couple covers you can take off in the grain tank to get access to the back end of those lines. We usually just unhook the steel lines and leave them there and route the new hoses along the right side of the combine. The trouble is figuring out which steel line is leaking because you can't see them, so I would suggest you just replace them all because they'll all leak eventually. You'll need metric fittings on the hoses, I can't remember the size but if you have a grimme dealer close by, such as HJV they usually have a good supply of the proper fittings, just make sure you measure twice and get the right length hoses.