Hydraulic bleed off

I've tried searching the internet but don't seem to find anything about this.

The rear remotes on the 886 bleed off. Enough that when I pull the bat wing mower I have to keep bumping the height up - it bleeds off fairly quick. If left to its own devices it would drop an implement completely in about 6 hours.

I assume seals need replacing. Are those within the remote valves behind the right battery? The loader is plumbed with a power beyond plate and it stays in the exact same spot indefinately.

There are no seals in the aux valve to hold the pressure. All the o rings are to prevent valve leak externally. It is a spool valve and all spools have to have clearance to operate. As they wear from use they leak more than when new. More pressure causes them to leak more. If your implement requires high pressure to hold it up it will leak down quicker. IH offered check valves that go in between valve and rear couplers that will positively prevent leak down. They are expensive and usually require different pipes etc to hook up.
But , all that being said, the first thing you want to determine is if your cylinder is causing the leak down. Is it a single action cyl? If so, forget the cyl. If double action cylinder, a leak in cyl will cause the pressure to become extremely high in both sides of the cyl. Called hydraulic phenomenon, (means it can be difficult to explain or understand). But, here is a real simple easy test. When you raise your implement, there should be high pressure only in the hose that is lifting and holding up the load. If you unhook the return hose, press open the coupler, no fluid should come out (oh it may squirt a little bit) but it should not continue to expel fluid. If it does, cylinder is leaking. If hose tip actually seems to suck in , the tractor valve is the problem. DO NOT UNHOOK BOTH HOSES TO TEST. A bad cylinder will hold up a load when both hoses are disconnected because the rod going into the cylinder is trying to displace oil and it has no place to go. Belive me, it is true, many many will argue. This pertains to a cylinder that the rod extends to lift the load, if the rod retracted to lift the load like many cylinders on loader bucket tilts do , a different method of testing is required.