Add a Double Pilot Check valve to Side Link Cylinder?

[DK35vince]

My Kioti DK45SE with a Fit Rite Top and Tilt system leaks down quite rapidly when I am brush hogging. If I set the mower for a 4 1/2" cut, the right skid is in the dirt within 15 minutes. Swapping lines between the two valves, the first valve leaks down maybe a few minutes slower than the second dealer installed optional valve. I haven't noticed any problem when using my rollover box blade, but then I haven't used it a whole lot yet. I have less than 30 hours on my tractor. Since float is not available with Kioti's valves, adding a DPOCV would solve my problem.

This is why I always have and will continue to recommend cylinders with a check valves for top and tilt.
I"ve had the same problem in the past and the cylinders with check valves solved it.

 

[Piston]

This is why I always have and will continue to recommend cylinders with a check valves for top and tilt.
I"ve had the same problem in the past and the cylinders with check valves solved it.

Here we go again.... unch:

 

[MHarryE]

Brian - I often use the side tilt when I am bush hogging - it's the rough terrain that we don't farm that gets brush hogged. Yes, both my valves leak, but I am accustomed to it and I don't even think about it anymore. If I leave the tractor sitting with my rear spear raised there is very little change. Leave my heavy rear tiller raised overnight and it's tilted big time in the morning. I've checked the specs on some very good control valves and their maximum leak rate at max pressure is significant. At first I was a bit annoyed when plowing (what little I do with the L5740) but then I discovered there was no perfect position in my varying soil type, varying terrain small fields in which I use the tractor instead of one of our large tractors that can't swing without knocking down a forest. Now if you put a position sensing device in your cylinder and had a digital display on which you could adjust degree of tilt with a feedback loop that maintains that angle, and doesn't cost anything - it's something to think about. I know the exact sensor and control system that would be perfect but at $7,500 probably beyond CUT buyer's budget.

 

[bumperm]

Here we go again - Or Not!! This is the approach I took to solve the cylinder creep problem

I installed this little guy on my tilt cylinder - 3/8 NPT 8 GPM BRAND PC37C PILOT-OP CHECK VALVE

I first ordered a dual pilot operated check valve as I mistakenly thought it would be simpler to install, but it was physically too large to fit nicely. I'm no hydraulics expert either, but it's not really all that complicated to install one of the above valves if one has a modicum of mechanical aptitude.

I mounted the single pilot operated check valve's outlet port directly to the lower (ram side) port on the cylinder using an adapter - this mounts the valve solidly, the other two connections to the valve are by flex hoses. On the top cylinder port I installed an inline "T" fitting and ran a hose to the pilot control port of the check valve. Locks up tight as a drum yet is completely controllable from the cab or when standing behind the tractor hooking up an implement (I can reach through the back window to the control levers so no need for rear mounted levers). This solution, costing about $75 total for valve, hoses, and fittings, is IMO better than an adjustable needle valve or undoing quick connects to lock a cylinder. The single disadvantage is that after you shut down the tractor moving the control lever will not allow gravity to move the cylinder as that requires positive pressure on the pilot port to "unlock" the check valve.

Not having installed a pilot controlled check valve before, I did not know if there was a preferred location for the restricter orifice, after or before the check valve (I'm using a .032" orifice on both top and tilt cylinder to slow things up some for more precise positioning). Asking the techs at Surplus Sales got the telephone equivalent of a blank stare - they had no clue. So I installed it closest to the cylinder inlet (i.e. between the POCV and cylinder) - - works fine there, cylinder runs smoothly with no jerkiness loaded or not. Note that the single POCV I installed only prevents creep in the extending direction - so far gravity prevents creep in the other direction. The top cylinder I purchased from Surplus came with a DPOCV already installed. Excellent quality 2X8.25X1.18 CAT I HYD DA TOP LINK CYL

bumper

If anyone wants pictures of the install, just ask.

 

[Piston]

Bumper, that sounds pretty slick!

Can you still use the float function with it? If so, it may be the ideal way to go.

 

[bumperm]

Bumper, that sounds pretty slick!

Can you still use the float function with it? If so, it may be the ideal way to go.

No, if the controller for the hydraulic outlets has a float function, it will no longer float with a pilot operated check valve plumbed into the system for that particular cylinder*. However, the 3 point lower link float function still works as normal being a separate hydraulic function.

Think of the POCV or DPOCV as mechanically the same as putting the original mechanical top and tilt links back on the tractor - adjustable, solid, and with no creep. Position it and that's where it stays. Does this by having the same effect as providing a positive lock for the cylinder to which it is attached. This would be the same as if you closed a needle valve or removed the quick connect couplings - - the cylinder ain't gonna move. The POCV does this with an internal valve that is only opened when it sees enough pressure on the *opposite* side of the cylinder. The effect is positive control with no cylinder creep.

In hydraulics, a DPOCV is often considered a safety feature, as a burst hose and most leaks will not result in an unintended collapse or movement.

bumper

 

[Piston]

Thanks for the info Bumper, good explanation! Unfortunately that wouldn't work for me. I won't give up my float feature.

 

[PSDStu]

Here we go again - Or Not!! This is the approach I took to solve the cylinder creep problem

I installed this little guy on my tilt cylinder - 3/8 NPT 8 GPM BRAND PC37C PILOT-OP CHECK VALVE

I first ordered a dual pilot operated check valve as I mistakenly thought it would be simpler to install, but it was physically too large to fit nicely. I'm no hydraulics expert either, but it's not really all that complicated to install one of the above valves if one has a modicum of mechanical aptitude.

I mounted the single pilot operated check valve's outlet port directly to the lower (ram side) port on the cylinder using an adapter - this mounts the valve solidly, the other two connections to the valve are by flex hoses. On the top cylinder port I installed an inline "T" fitting and ran a hose to the pilot control port of the check valve. Locks up tight as a drum yet is completely controllable from the cab or when standing behind the tractor hooking up an implement (I can reach through the back window to the control levers so no need for rear mounted levers). This solution, costing about $75 total for valve, hoses, and fittings, is IMO better than an adjustable needle valve or undoing quick connects to lock a cylinder. The single disadvantage is that after you shut down the tractor moving the control lever will not allow gravity to move the cylinder as that requires positive pressure on the pilot port to "unlock" the check valve.

Not having installed a pilot controlled check valve before, I did not know if there was a preferred location for the restricter orifice, after or before the check valve (I'm using a .032" orifice on both top and tilt cylinder to slow things up some for more precise positioning). Asking the techs at Surplus Sales got the telephone equivalent of a blank stare - they had no clue. So I installed it closest to the cylinder inlet (i.e. between the POCV and cylinder) - - works fine there, cylinder runs smoothly with no jerkiness loaded or not. Note that the single POCV I installed only prevents creep in the extending direction - so far gravity prevents creep in the other direction. The top cylinder I purchased from Surplus came with a DPOCV already installed. Excellent quality 2X8.25X1.18 CAT I HYD DA TOP LINK CYL

bumper

If anyone wants pictures of the install, just ask.

I would like to see the pics of your install.

Thanks!