IH766 remote hydraulics

I have a IH766 that I was discing with today and had no problems with the hydraulics lifting but when I finished and was preparing to unhook from the tractor I noticed while idling that the remote cylinder was bleeding down ever so slowly. I am putting together a gauge to measure the hydraulic pressure from the remotes to determine if a pump problem. Where should I start looking if not the pump. I was round baling last week and had no problem raising the baler door but did have a problem with the door coming open before I had a full tight bale at times. Could anyone tell me if this is the pump or what else I should be looking for. Thanks in advance and read here all the time but rarely submit any posts.. I do appreciate everything I learn here. The people posting are my teachers as I consider myself average in mechanical ability but need someone to point me where to go to tackle..

The most common cause for a cylinder to creep is an internal seal leaking.

If there is more than one cylinder on the circuit, it can be a different cylinder. The oil will take the path of least resistance and can be difficult to diagnose.

About the only way is to isolate the cylinder, apply pressure and observe oil bypassing the seal, or block the port, apply force to the cylinder, see if it moves.

You're not setting so that you are bumping the lever with your leg are you? I have to watch that on my 806 or the 856 when baling I can just bump it enough it would release the latch to the door on it.

I would not think it is your pump. Either an internal leak in your cylinder or your control valve not seating properly. Obviously, your pump has adequate pressure to raise the disk. Once your implement lifts and the valve returns to neutral, the pump is not involved in holding the implement in the raised position. This problem should be easy to diagnose. Raise the disk, shut tractor off and disconnect your hoses. If the disk continues to settle, it is your cylinder. If not, it is your valve that is at fault. The only other possibility would be an external leak, in which case you would see a wet spot. Be careful.

Most likely problem is the remote valves are worn out and leaking internally. No rebuilding possible. Only solution I know of is a different spool valve or finding the factory two way lock valve that was optional on these tractors

The pump has nothing to do with holding pressure.

If it were just the disc drifting down I would suspect the cylinder on the disc, but since the baler is losing pressure as well, it is most likely the valve under the seat on the tractor.

Try the other remote if the tractor has two. It may not be as worn and will hold. At least you can get the job done and push back the teardown until there isn't so much work to do.

With the teardown, I find putting the valves back together without them leaking profusely to be a frustrating task. The only people able to put them back together so they don't leak are old school IH mechanics, which are hard to find these days as most are retired in their 70's.

Steve has given you the answer to your question, but here is a little more of a theoretical answer or example. Think of the cylinder as a medical syringe, no needle on it for this example. Once fluid is drawn in it and air is removed holding your finger on the end will not let the plunger be pushed in, that is how your cylinder works. Unless fluid leaks by the syringe plunger which is like the cylinder piston and seals or past your finger which is like the hydraulic valve the plunger cannot be pushed in. When the hydraulic remote is in the center position the remote valves are just holding pressure (or should be if not leaking by) the pump is not in the equation at all at this point. The pump only comes into action when flow or pressure is required when you move the remote lever into the raise or lower position. If the action of the cylinder is moving fast enough and with enough force to do the work you want the cylinder to do the pump is fine. I realize the cylinders you are using are likely double acting so the syringe idea is a little simplistic, but still the trapped fluid in the cylinder on both sides of the piston is what makes it work as in hold a position.

If your tractor is equipped like ours was there is two remotes for the rear. Switch sides if so and try again. I agree with the other comments. Also if the tractor has not been changed there were little handles by the couplers that if you turn them 90 degrees it would disconnect the circuit, you could test there.- I know many were changed but I though I would ask.

Thanks to everyone for the replies. I will try fixing when I get time to take out of service.