Question for top n tilt users

[KatieL3710hst]

Question for top n tilt users

I have top n tilt on my Kubota 3710 hst.
I don't have any problem with the tilt, but the top link is another story.
when I use my box blade the cylinder on the top link compresses when the box blade starts filling
with dirt, sometimes as much as 3" and returns when the load is released. /forums/images/graemlins/mad.gif
I told the dealer I bought it from and they said Its suppose to do that. /forums/images/graemlins/confused.gif
Well I may be new to top n tilt but I don't think its suppose to compress that much. /forums/images/graemlins/tongue.gif
After many MANY phone calls to the dealer, they said it was the quick connects, so they replaced them.
No difference same problem. /forums/images/graemlins/frown.gif
After many more phone calls to the dealer, they said it was the cylinder, so they replaced it.
No difference same problem. /forums/images/graemlins/frown.gif
Now they say its the remote valves, but they won't replace it, instead they want to try and rebuild it, and said it will take 2 to 4 weeks.
I was hoping one of you top n tilt users would have some Ideas or advice to what it might be?
I've switched the top link hoses with the side tilt hoses (the quick connects that is, so the tilt remote would operate the top link and the top link remote would operate the tilt, no
difference, the top link still compresses when under load and returns when load is released.

Thank you in advance for any help and advise. /forums/images/graemlins/smile.gif

Les

 

[Anonymous Poster]

Not familiar with that Kubota, does it have draft control ? if so this could be your problem. If it does not have draft control it sounds like air in system.

 

[JimMc]

Install a double pilot operated check valve like the ones CCI has shown in the attachments forum. The only way fluid can exhaust from the cylinder is for hydraulic pressure to be applied to the opposite port. Stops the drift. Short of that, if the cyliner returns to its original position after releasing the load, bleed the cylinder - air will compress and return like an air shock. Hydraulic fluid will not compress.

 

[Rowski]

As JimMC mentioned you need the doudle piloted check valve. CCI has top links with them installed.

CCI post

I think that it is possible that you may have fluid leaking internal in the cylinder. I'm pretty sure the doule piloted check valves would keep the cylinder from moving even if you cylinder was leaking internally.
I started a topic about hydraulic top links. Has some pictures from CCI showing his cylinder setup.

 

[markct]

rowski, the pilot operated check valves will not keep your cylinder from moving if its leaking internaly, all it does is keep fluid from being able to go back out the port, if the fluid is leaking past the piston inside it will still creep

 

[HayDR]

Concerning welded cylinders:
Most often the selection valve and or couplers will have the greatest incidence of "bleed by"more than a cylinder having a by pass problem. Welded cylinders of today are made to exacting tolerances much better than cylinders of yester years and or Tie-Rod cylinders. The key to longevity is proper maintenance of the hydraulic filters in the tractor. If the hydraulic fluid has trash in it will eventually cut the O rings and packing used and cause bleed by problems in the entire system.

 

[Rowski]

This is true for single pilot operated check valves. This top link has a double piloted check valve, a valve for each side of the piston in cylinder. If the fluid is creeping by to the other side wouldn't the other pilot valve keep it from leaking out? I'm curious?

I know the wreck we have at work has polit valves because if the pump is off and you move the spool valves nothing moves. Hence the safety.

 

[Anonymous Poster]

Don't forget that you have 2 chambers with different max. volume in double acting cylinder (two different cross section working area). When cylinder is compressed, you have smaller chamber (with rod inside) filled with oil, and when cylinder is extended (with rod outside), bigger chamber is filled with oil. Double pilot valve (or stop valve, as I called it before) blocks oil flow outside the cylinder. And if you have internal leak in cylinder pack, oil can flow only in direction from smaller chamber to bigger, and make vacuum in bigger chamber. Another way of oil flow is not possible, because, oil is not compressable.
That means: if you leave your attachment raised on 3pt, and have internal leak in top link cylinder, it will extend during time, and opposite - if you leave cylinder extended, push force (pressure) will NOT retract (compress) it.
Hope this helps. /forums/images/graemlins/wink.gif

 

[KatieL3710hst]

No, I don't have draft control.
I thought it was air also.
I've switched the inlet & outlet lines while operating the remote valves to try and get the air out, but problem still present.

Thank you. /forums/images/graemlins/smile.gif

Les

 

[KatieL3710hst]

Can this double pilot operated check valve be purchased separately, or do I have to buy a cylinder with it already installed?
If it can be purchased separately, Where would I find one and about how much do they cost?

Thank You. /forums/images/graemlins/smile.gif

Les

 

[hayden]

Does the cylinder compress and then spring back, or does is slowly lose it's position and then requires use of the control lever to return it to the original position?

If it compresses and then springs back once the load is removed, it's almost certainly air trapped in the cylinder. The air compresses under load, then springs back when the load is removed.

If the cylinder shifts position under load, but requires use of the control levers to restor position then there is leakage or bypass in either the cylinder or valve.

The check valves being described I always thought were to prevent momentary sagging at the instant you engage the control lever to move the cylinder. I didn't think they had any effect if the lever was in a stationary position. That said, I'm not an expert.

To get air out, disconnect the cylinder end and run it through several full extend/retract cycles. Usually this will get the air out. If not, the positioning of the hoses adn cyl tip angle may be causeing air to get trapped at some intermediate high point in the cylinder or hose. Temporarily repositioning the cylinder/hoses so that any air has an upward path back to the control valve may help trapped air escape.

The only other thing I can think of, and it seems unlikely, is that one of your hoses is defective and is able to expand under pressure. The ballooning effect would behave much like air trapped in the cylinder.

 

[Anonymous Poster]

Hayden, I believe you have it. With the cylindermounted it might not be able to run to full extension/retaraction to expel the air.

 

[Anonymous Poster]

I have a gearmore top and tilt on my 3710 and have'nt noticed any drifting when pulling a 6' gannon box, it sounds like air is getting in the cylinder someway by the fact that it springs back. runing the cylinder to both ends should clear the air out, possably something in the control valve could be alowing the air in /forums/images/graemlins/confused.gif