Need Help: Sizing Tilt Cylinder

[Work Horse]

Hey All,

I have a B7200 Kubota with an aftermarket loader on it. I'm having issues with the tilt cylinder maintaining it's position under load, and I find myself constantly bumping up the tilt lever on the joystick. Coupled with the fact that I'm adding a larger bucket to the loader, I suspect I'm only going to have more issues.

The loader currently only has one center mounted tilt cylinder, is it worth going to a setup with two cylinders? Or should I try and source one BEEFY cylinder and keep my setup relatively the same as it is now?

TIA

 

[chpmnsws6]

Just upgrade your one cylinder. On our bigger Massey, it'll curl 2500 pounds with its single cylinder (but won't lift it with the arms)

 

[Work Horse]

Just upgrade your one cylinder. On our bigger Massey, it'll curl 2500 pounds with its single cylinder (but won't lift it with the arms)

Huh, no kidding! Is there a certain threshold to stay within? I'm sure I should be looking for something similar in size to what I have now, but with a higher PSI flow/rating? I haven't really had to mess with hydraulics all that much, so I don't know what I'm looking for.

 

[Henro]

Chances are your problem is leakage in the control valve, rather than the cylinder.

Is the cylinder rod extending or moving into the cylinder when you have to use the control valve to compensate?

If the rod is moving into the cylinder, chances are high the issue is in the control valve itself, and not the cylinder.

If the rod is extending from the cylinder, it could be a cylinder problem, or still the control valve, I suppose. NOT an expert here. But there are others here that can give more help in the analysis of your issue.

If you report which way the rod is moving this will help you get a definitive answer...You certainly do not want to buy a cylinder you did not need, only to find the issue is with the control valve.

 

[Work Horse]

Chances are your problem is leakage in the control valve, rather than the cylinder.

Is the cylinder rod extending or moving into the cylinder when you have to use the control valve to compensate?

If the rod is moving into the cylinder, chances are high the issue is in the control valve itself, and not the cylinder.

If the rod is extending from the cylinder, it could be a cylinder problem, or still the control valve, I suppose. NOT an expert here. But there are others here that can give more help in the analysis of your issue.

If you report which way the rod is moving this will help you get a definitive answer...You certainly do not want to buy a cylinder you did not need, only to find the issue is with the control valve.

Ultimately the answer is dependent upon how much weight is in the bucket...

If I have a full bucket of stone/dirt and the bucket starts to tilt down, I can generally bump the stick and tilt the bucket back up again.

If I have a heavy load extended out on pallet forks, the cylinder generally won't have the umph to retract the rod. If I drop the bucket onto the ground, I can bump the tilt and it will retract the bucket.... but that is short lived once the load is lifted off of the ground again.

 

[Work Horse]

This has me wondering...

My 3PH is constantly "falling down" under load as well. I have to keep bumping up on the lever to keep it up. Does that somehow tie into the control valve as well?

The loaders vertical cylinders don't seem to have any issue falling off, unless the tractor is shutoff... then it will slowly bleed down.

 

[TheOldHokie]

Hey All,

I have a B7200 Kubota with an aftermarket loader on it. I'm having issues with the tilt cylinder maintaining it's position under load, and I find myself constantly bumping up the tilt lever on the joystick. Coupled with the fact that I'm adding a larger bucket to the loader, I suspect I'm only going to have more issues.

The loader currently only has one center mounted tilt cylinder, is it worth going to a setup with two cylinders? Or should I try and source one BEEFY cylinder and keep my setup relatively the same as it is now?

TIA

Piece of cake. Stay with one cylinder and increase bore one size if you want more breakoit force.

What is rhe bore and stroke of yoir current cylinder?

Dan

 

[TheOldHokie]

This has me wondering...

My 3PH is constantly "falling down" under load as well. I have to keep bumping up on the lever to keep it up. Does that somehow tie into the control valve as well?

The loaders vertical cylinders don't seem to have any issue falling off, unless the tractor is shutoff... then it will slowly bleed down.

Bleed off on tje 3pt and loader are not related.

The buvket cylinder is almost surely the problem with the loader. Easy to test the cylinder.

Does the 3pt hold position when the tractor is running?

Dan

 

[Work Horse]

Piece of cake. Stay with one cylinder and increase bore one size if you want more breakoit force.

What is rhe bore and stroke of yoir current cylinder?

Dan

I haven't determined that yet... I actually just finished watching a couple videos on that matter and will find out what I have later this afternoon when I get out of work....just going off visual memory the bore must be somewhere in the 2.5-3" range. It looks to be the same thickness as the lift cylinders.

 

[Work Horse]

Bleed off on tje 3pt and loader are not related.

Does the 3pt hold position when the tractor is running?

Dan

It does when it is in the "full" up position. There is a notch that seems to hold the lever in place at the upmost position. The lever feels loose and tends to droop down...could just be a retention issue within the level itself...?

 

[TheOldHokie]

It does when it is in the "full" up position. There is a notch that seems to hold the lever in place at the upmost position. The lever feels loose and tends to droop down...could just be a retention issue within the level itself...?

Yes, the "notch" locks the valve in the full up position and it also cause the pump to run at full pressure against the relief valve. Thats not a good way to extend pump life.

Sounds exactly like mine. In the intermediate positions the lever is drifting down taking the lift with it. Tighten the friction mechanism (nut) that holds the lever at its set position.

Dan

 

[Henro]

Yes, the "notch" locks the valve in the full up position and it also cause the pump to run at full pressure against the relief valve. Thats not a good way to extend pump life.

Sounds exactly like mine. In the intermediate positions the lever is drifting down taking the lift with it. Tighten the friction mechanism (nut) that holds the lever at its set position.

Dan

Dan, I’m obviously missing something. Apparently we know now that the issue is with the cylinder extending and the OP having to use his control valve to retract the cylinder to keep the bucket or forks in the position he wants them.

I think the ability of the loader to move/lift. under load is a different issue than the cylinder extending on its own when the control valve is centered.

Perhaps I misread what the OP is saying. But it sounds to me like there are two questions in his original post. One is why the cylinder extends when it shouldn’t, and the second is what does he need to do to increase the ability of the loader to tilt/lift more weight on his forks.

Also, on my loader, the control stick is moved up and down to raise and lower the loader, and left and right to tilt the bucket. So it seems like if there was a problem in the valve not holding center, it would be more likely to show up with the loader itself drifting, rather than in the bucket tilt, since the weight of the arm, pushing down, should not cause the bucket to go up or down since that requires a left or right movement of the control stick.

That’s my logic. Seems to be different than yours, and you’re the one that knows hydraulics extremely well. so if you can take a moment to explain what I’m missing, I would appreciate it, and it could be helpful to others as well.

edit: of course, the OP could always increase the size of his cylinder to do that part of what he wants. Larger cylinder, all other things remaining the same, would increases ability to tilt more weight, but slow down the rate of change of the bucket position a bit.

I get that and probably that’s the best first thing to do and then if the drifting issue of the bucket tilt remains, he can address the possible valve issue I suppose.

 

[TheOldHokie]

Dan, I’m obviously missing something. Apparently we know now that the issue is with the cylinder extending and the OP having to use his control valve to retract the cylinder to keep the bucket or forks in the position he wants them.

I think the ability of the loader to move/lift. under load is a different issue than the cylinder extending on its own when the control valve is centered.

Perhaps I misread what the OP is saying. But it sounds to me like there are two questions in his original post. One is why the cylinder extends when it shouldn’t, and the second is what does he need to do to increase the ability of the loader to tilt/lift more weight on his forks.

Also, on my loader, the control stick is moved up and down to raise and lower the loader, and left and right to tilt the bucket. So it seems like if there was a problem in the valve not holding center, it would be more likely to show up with the loader itself drifting, rather than in the bucket tilt, since the weight of the arm, pushing down, should not cause the bucket to go up or down since that requires a left or right movement of the control stick.

That’s my logic. Seems to be different than yours, and you’re the one that knows hydraulics extremely well. so if you can take a moment to explain what I’m missing, I would appreciate it, and it could be helpful to others as well.

Yes he is aking multiple questions

The bucket is always going to drift down due to spool leakage in the valve. But that drift will be pretty slow and his is pretty fast which is why I suspect the seals in the cylinder.

He is also worried about the curl (break out) force he gets from a single bucket cylinder and what to do to increase it. Increasing the bore of the cylinder will obviously do that. The question is how much. Heres a bit of arithemetic to show its a lot:

The working area of the curl side of the piston is the piston area minus the rod area.

If he currently has a 2.5" cyinder with 1" rod the working area of the piston is 3.14 sq-in.

If he replaces it witj a 3" cylinder with a 1.5" rod the working area increases to 5.3 sq-in. That increases breakout by a factor of 5.3/3.14 = 1.69. That's a 69% inctease in breakout force which is very substantial.

Dan

 

[Work Horse]

Yes, the "notch" locks the valve in the full up position and it also cause the pump to run at full pressure against the relief valve. Thats not a good way to extend pump life.

Sounds exactly like mine. In the intermediate positions the lever is drifting down taking the lift with it. Tighten the friction mechanism (nut) that holds the lever at its set position.

Dan

I would be siked if the fix is that simple... I'm pretty sure the lever/assembly has been messed with at one point or another.

I didn't know about the pressure against the relief valve tidbit but that makes sense now that you say it. I have noticed in the past that the position of the 3ph has a slight impact on the HST drive and the loader function speed.

 

[Work Horse]

Dan, I’m obviously missing something. Apparently we know now that the issue is with the cylinder extending and the OP having to use his control valve to retract the cylinder to keep the bucket or forks in the position he wants them.

I think the ability of the loader to move/lift. under load is a different issue than the cylinder extending on its own when the control valve is centered.

Perhaps I misread what the OP is saying. But it sounds to me like there are two questions in his original post. One is why the cylinder extends when it shouldn’t, and the second is what does he need to do to increase the ability of the loader to tilt/lift more weight on his forks.

Also, on my loader, the control stick is moved up and down to raise and lower the loader, and left and right to tilt the bucket. So it seems like if there was a problem in the valve not holding center, it would be more likely to show up with the loader itself drifting, rather than in the bucket tilt, since the weight of the arm, pushing down, should not cause the bucket to go up or down since that requires a left or right movement of the control stick.

That’s my logic. Seems to be different than yours, and you’re the one that knows hydraulics extremely well. so if you can take a moment to explain what I’m missing, I would appreciate it, and it could be helpful to others as well.

edit: of course, the OP could always increase the size of his cylinder to do that part of what he wants. Larger cylinder, all other things remaining the same, would increases ability to tilt more weight, but slow down the rate of change of the bucket position a bit.

I get that and probably that’s the best first thing to do and then if the drifting issue of the bucket tilt remains, he can address the possible valve issue I suppose.

Sorry for the confusion... one question led to another

I'm definitely looking into a bigger tilt cylinder regardless of the control valve... it has seemed to be an issue since day 1. Although I don't discredit your point on the control valve..... If the tilt function is still an issue after cylinder replacement that will be a dead giveaway.

 

[TheOldHokie]

I would be siked if the fix is that simple... I'm pretty sure the lever/assembly has been messed with at one point or another.

I didn't know about the pressure against the relief valve tidbit but that makes sense now that you say it. I have noticed in the past that the position of the 3ph has a slight impact on the HST drive and the loader function speed.

That notch is meant for use with the optional factory rear hydraulic outlet. It replaces the cap on the 3pt hydraulic cylinder and is why the pump is deadheaded into the cylinder.

Dan

 

[TheOldHokie]

Sorry for the confusion... one question led to another

I'm definitely looking into a bigger tilt cylinder regardless of the control valve... it has seemed to be an issue since day 1. Although I don't discredit your point on the control valve..... If the tilt function is still an issue after cylinder replacement that will be a dead giveaway.

No need to guess. To test the cylinder :

1) Raise the bucket, operate the handle to roll if full back and secure it with a strap.

2) Disconnect the hose at the base end of the cylinder and plug/cap the port in the cylinder

3) Remove the strap, increase engine to roughly 3/4, and then move loader control handle to roll back position and hold it there. If the cylinder extends the seals are bad. If mot the seals are fine.

Dan

 

[Henro]

No need to guess. To test the cylinder :

1) Raise the bucket, operate the handle to roll if full back and secure it with a strap.

2) Disconnect the hose at the base end of the cylinder and plug/cap the port in the cylinder

3) Remove the strap, increase engine to roughly 3/4, and then move loader control handle to roll back position and hold it there. If the cylinder extends the seals are bad. If mot the seals are fine.

Dan

Call me practical, but at this point understanding what the situation is, I would think there’s no reason to test the existing cylinder since it’s going to be replaced anyway regardless of whether it’s bad or good.

Be interesting to hear what the net result is after the cylinder is replaced.

Well, I guess testing it might not be a bad idea if there was an intention to sell it to somebody or use it in the future for something else…

 

[TheOldHokie]

Call me practical, but at this point understanding what the situation is, I would think there’s no reason to test the existing cylinder since it’s going to be replaced anyway regardless of whether it’s bad or good.

Be interesting to hear what the net result is after the cylinder is replaced.

Well, I guess testing it might not be a bad idea if there was an intention to sell it to somebody or use it in the future for something else…

I did not realize tjat decision had been made but I think I would test it anyway. Only takes a few minutes an he will know the status of his spare cylinder.

Dan

 

[mikester]

Hey All,

I have a B7200 Kubota with an aftermarket loader on it. I'm having issues with the tilt cylinder maintaining it's position under load, and I find myself constantly bumping up the tilt lever on the joystick. Coupled with the fact that I'm adding a larger bucket to the loader, I suspect I'm only going to have more issues.

The loader currently only has one center mounted tilt cylinder, is it worth going to a setup with two cylinders? Or should I try and source one BEEFY cylinder and keep my setup relatively the same as it is now?

TIA

Great idea! You have a limited lift capacity machine and you are going to make it stronger by doubling the weight of bucket cylinders.

Buy a bigger machine designed to handle the loads you need to lift. Putting two handles on your shovel won't make you lift heavier loads.