I've recently purchased an old R30 trencher and while I'm excited about the prospects of making money with this machine, hydraulics are foreign to me. The pictures below show a hose that has connected two of the hydraulic ports together. I'm assuming these ports are perhaps for the backhoe attachment, but I don't know why they would be connected like this. When I operate the blade on front, this hose twitches and seems to swell. Also, operating the front blade seems to put a lot of stress on the engine. Other than several hydraulic leaks and drips, this is all I have for now.
It looks like those are hydraulic ports for some auxiliary hydraulics. The hose looks like its a loop with quick disconnects. Not sure why they would put that loop on, unless the quick disconnects were leaking.
Could be for a backhoe and need to be connected together so you don't dead head the pump. Could also be for an angle cylinder for a blade. Follow the lines back and see if they go to a control valve or come directly from the hyd. valve block to the front of the machine. It's possible something is leaking in the valve assembly putting some pressure on the hose(s). Another thing you could try after seeing where the lines come from is to remove the quick connects and put the 2 open hoses in a bucket. Then crank the engine, preferably without starting it and see if oil comes out one or both of the hoses. If oil is constant the lines are likely for a backhoe and need to stay connected. Another option is to tee in a pressure gauge to see how much pressure is in the lines and if it changes when you operate the blade.