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Charlie 12-07-2012 10:21:25 24.62.108.143 Report to Moderator	I've been following this discussion. It seems to me that even if there is a badly leaking piston seal in one of the cylinders, you would still be able to detect either by slight hose movement or by listening at the cylinder whether the valve is sending fluid there. If there is a relief built into the connector at the cylinder, as there is on my Drott skid shovel's 4-way cylinder, you could also detect flow there the same way. The main valve relief must be OK because it protects all circuits, I think. Will be interesting to hear about your next experiment. [Reply]   [No Email]
tpmx 12-08-2012 07:27:17 50.51.180.233 Report to Moderator	Re: Drott Skidloader in reply to Charlie, 12-07-2012 10:21:25   Ok this morning i switched the lines over to the other spools. I have the same identical problem. I still cant picture how a bad packing on the piston would allow the cylinder to still have down pressure ,seems it would bypass in both direction. Now to see if theres a relief valve at the lift end of each cylinder. My other thought is what if a hose to one of the cylinders was internally restricting oil. Would the other cylinder still try to lift the loader or would it be mechanically impossible? I know the hose to the lift side of the right cylinder is only a few years old but the other is probably original or at most pretty old. I cant see a valve any where on the lift side unless it built inside the cylinders somehow [Reply]  [No Email]
Charlie 12-09-2012 04:19:38 24.62.108.143 Report to Moderator	Re: Drott Skidloader in reply to tpmx, 12-08-2012 07:27:17   I suppose that if one line were plugged, the other would try to lift, but it would face some suction pressure as the other cylinder would be creating a vacuum where fluid (or air from the rod packing) were not available. Here are my latest thoughts: 1. Try very hard to listen for any fluid movement or even a twitch in the hoses at the cylinders when you try to lift. Maybe crack a hose at the cylinder on the pressure side for lift. I think you will get something. 2. The pressure may not be enough to lift, even though you can get downpressure. Your main pressure relief valve is presumably a pilot operated relief, and there is a procedure for adjusting that. I made a tool for mine and adjusted it up. If you don't have a diagram, I could send you the page from my IH TD340 hydraulics manual, probably slightly newer than your machine. 3. There could be a problem with a check valve in the valve body, either blocking flow or somehow relieving pressure through another circuit. 4. The pump could be too weak to lift. [Reply]  [No Email]
tpmx 12-09-2012 06:02:54 50.51.180.233 Report to Moderator	Re: Drott Skidloader in reply to Charlie, 12-09-2012 04:19:38   Ill do some further testing. I am going to drill and tap a pipe plug for a gauge and pressure test the original lift port now that I can access it easily This will tell me whats going on with hopefully the pump and valve. Is funny there is no reaction in the cylinders or hoses on the lift stroke. [Reply]  [No Email]
Charlie 12-09-2012 10:22:13 24.62.108.143 Report to Moderator	Re: Drott Skidloader in reply to tpmx, 12-09-2012 06:02:54   I would still inspect those poppet check valves in the top of the valve body, at least if it's like mine. That could explain the noise you're getting in the valve. [Reply]  [No Email]
tpmx 12-09-2012 11:06:26 50.51.180.233 Report to Moderator	Re: Drott Skidloader in reply to Charlie, 12-09-2012 10:22:13   Ok but I only have one releif valve on the top right of the valve [Reply]  [No Email]
Charlie 12-09-2012 17:54:06 24.62.108.143 Report to Moderator	Re: Drott Skidloader in reply to tpmx, 12-09-2012 11:06:26   The check valves are very simple and under hex plugs in the top of my valve, perpendicular to the axis of each spool. These are separate from the relief valve. I could send you a schematic of mine if you would like. Just send me your Email address. Mine is open. [Reply]  [No Email]