I had the same leak on my 863. Took it to the Dealer in Flagstaff, AZ where they tried to change the O-ring on the pump line outlet (not leaking before I took it to them). Then when they couldn't get it tightened back up, they left it a thread loose, which of course, caused another worse leak. I had them try to repair other items at the same time but every item they did, I had to tear back apart and fix it correctly. Called Phoenix Bobcat and asked about buying an o-ring kit for the control valve because I was going to pull it out to fix it. He asked why would I do that. His mechanics repaired them all the time without removing the body. When I asked how much he said $150 including parts and it would be done in half a day. Had it back in a day, repaired correctly. Since then I've done all my own repairs but that was a very bad experience with the wrong dealer and a very good experience with the right dealer. That was in 2014 and the valve body has not leaked since.