hydralic toplink

[Dallas_Lilly]

Originally Posted by ovrszd

Where'e the Mad Referee when ya need him!!!! I'll try to address this issue using what I learned from Mad.

What you have described is compression. You cannot compress or expand hydraulic fluid. The only thing that could be present in your system that would compress or expand is air. The only other thing that could cause this would be hoses so soft that they expand and shrink with pressure or a cylinder barrel that similarly changes shape. These last two are highly unlikely.

If your cylinder is leaking past the internal seals, it would not return at all. It would simply close or open until the pressure is reduced below the leak tolerance and then stay static in that position until excessive pressure were again introduced. Even a DPCV will not help if the cylinder is leaking internally. A DPCV prevents the exchange of fluid between one cylinder fitting and the other. Internal cylinder leaks do not create that situation. No fluid moves at the cylinder barrel fittings.

If your valve is leaking, it will act the same way I described above. The difference would be that the DPCV would prevent cylinder drift if it's caused by valve leaks.

So, sounds like you have air in your cylinder?? It won't take very much air. A thimble full of air in the cylinder or pressurized system would allow the cylinder to move considerably. And again, after the pressure was reduced, the cylinder would somewhat return to it's original position.

Usually a cylinder will purge itself without help just from use. But it's possible to create a system that won't allow the cylinder to do that. For example, if enough hydraulic fluid can be introduced to one hose of the cylinder to extend or collapse that cylinder to it's limit without pushing all the air out of the opposite hose into the open center of the valve, then that remaining air is trapped in the cylinder plumbing system. It will simply be pushed back into the barrel of the cylinder when fluid is introduced into the opposite hose. To fix this will require uncoupling one hose from the tractor, unscrew the coupler from the hose end to create an open end, then gently apply hydraulic pressure to the other hose using the valve. This will spit out whatever fluid and air that is on that side of the cylinder seals. After the cylinder has reached the end of it's travel, holding the open hose vertical, pour it full of fluid and reinstall the coupler.

Sorry for the ramble. Hopefully some of it will be helpful.

No need to apologize, this makes perfect sense to me, and now that I think about it the condition has seemed to improve as usage has increased. I have not had my box blade on there for about a month now and have used my mower allot and have used the HTL every time I use the mower to load and unload on the trailer. I will have to install the box blade and see if the air maybe worked its way out with all the cylinder usage. I do not think that I have ever extended the cylinder all the way since I installed it for fear of ripper teeth in the tires, if I extend it maybe that will help. Thank you for responding and giving your knowledge and suggestions.