GC1700 series fast dump loader function??

[atsah]

Sorry, but the physics of the circumstance does not support your observation.[/I]

I went out this morning and tried different things with the loader to make sure I wasn't mistaken after I read you're post, it does what I posted earlier and both tractors labored in doing so. My JD does the same, the chances of me having two "special" loader valves on two different brand tractors is pretty slim, my luck isn't very good..

 

[MaineGuy1]

I went out this morning and tried different things with the loader to make sure I wasn't mistaken after I read you're post, it does what I posted earlier and both tractors labored in doing so. My JD does the same, the chances of me having two "special" loader valves on two different brand tractors is pretty slim, my luck isn't very good..

Yes, but I think you are proving his point. If it is lifting your tractor off the ground you are not in any type of fast dump.
Edit: Ok, sorry, I re read the other posts. I always thought fast dump just released the hydraulic fluid but maybe that is not the case. I guess I need to ask my dealer, and maybe they won't even know, lol.

 

[atsah]

you are not in any type of fast dump.

Yes I am.. It doesn't matter to me what someone else thinks about it, it works the way it works when I use what I have, some of these conversations assume someone isn't telling the truth for some foolish reason.

I went out this morning and proved it to work the way I thought it did, I don't know what to tell ya other than there is nothing more for me to add to this conversation. So carry on fellas..

 

[MaineGuy1]

Yes I am.. It doesn't matter to me what someone else thinks about it, it works the way it works when I use what I have, some of these conversations assume someone isn't telling the truth for some foolish reason.

I went out this morning and proved it to work the way I thought it did, I don't know what to tell ya other than there is nothing more for me to add to this conversation. So carry on fellas..

Read my complete post and I admitted I could be wrong. Maybe you didn't read it all.

 

[atsah]

Read my complete post and I admitted I could be wrong. Maybe you didn't read it all.

I read it, I'm just getting aggravated with people that think everyone is a moron, I have been messing with tractors since the 60's and know my fair share about them. I didn't mean to get on you about it, sorry..

AND you edited your post after I read it. So keep that in mind in the future, once you post people read it and don't go back and read it again..

 

[JWR]

I respectfully disagree, if you float the bucket using fast dump, and it's flat on ground, if you attempt to push against a snow or dirt mound, it WILL lift the front wheels as the bucket rotates the front lip downward, found out this learning years ago what position does what on the loader stick!

What you describe is the forward motion of the tractor causing the bucket (whose tip is caught in the ground or something solid) to rotate downward as the loader frame rides up over it. Sure, that can and does happened which does not contradict my point at all. Really that has no relationship to a fast dump feature. Atsah did not describe any forward motion into something hard/immovable, he was just talking snow.

I'm saying that 1) a quick dump feature on a front end loader puts the bucket into free-fall or the same thing as float dumping rotation with only gravity driving the bucket downward. And 2) that if Atsah's FEL bucket lifted the front end off the ground under hydraulic force (not forward motion riding up over an obstacle) then it was not in fast dump mode at that point.

 

[aczlan]

I'm saying that 1) a quick dump feature on a front end loader puts the bucket into free-fall or the same thing as float dumping rotation with only gravity driving the bucket downward. And 2) that if Atsah's FEL bucket lifted the front end off the ground under hydraulic force (not forward motion riding up over an obstacle) then it was not in fast dump mode at that point.

Respectfully, you are incorrect. As I said before, the quick dump or regen dump feature ties both hydraulic lines to the bucket dump cylinders together with the high pressure input line from the hydraulic pump (or the next valve closer to the hydraulic pump).
It works because of the difference in surface area between the base end of the cylinder and the rod end of the cylinder.

Because the rod end has a greater surface area, the force pushing the bucket to dump is greater than the force pushing the bucket to curl.

Aaron Z

 

[JWR]

aczlan: That's OK. We disagree. You could be right. I don't think so, but honorable people disagree honorably ! I'll do some homework.

I also want to mention that I regret Atsah came away a few posts back with an impression "people that think everyone is a moron." I never intended anything remotely similar to that and I'm betting neither did MaineGuy1. These machine mechanisms are often complex and I think we have all seen subtle differences between brands, models, situations, etc. On top of all that, it is difficult to be 100% accurate (getting across exactly what we mean, be it right or wrong) based on just using English. To me there's nothing wrong with honest disagreement and I suspect we learn more from those than we do from bland concurrence.

These forums are valuable because people are able to freely describe a problem, ask a question, express opinion, give benefit of experience, and explain how they believe something works. It would be fairly miraculous if we didn't disagree at times. In my 8 years on here and more than 1300 posts I can only recall once that I felt another guy was so far out of line that he earned a place on my permanent sh list. None of that applies to any of you on this thread.

 

[aczlan]

aczlan: That's OK. We disagree. You could be right. I don't think so, but honorable people disagree honorably ! I'll do some homework.
.

Do you have regen dump on your tractor? If so, can you try something to prove if you are correct or not?
1. Put the loader lift circuit into float with the bucket curled, the engine running and the tractor not moving
2. Move the loader to put the bucket cylinder into regen dump position
If you are correct, it the bucket will move until the bottom is flat, then stop.
If I am correct, the bucket will keep moving until it goes to full dump (you might need to give it a little throttle to make it do that).
I say this because I have a tractor with a regen dump circuit on it that I had to disable to make the snowblower chute angle work, so I looked into what makes it work (I initially thought the motor was bad)
Here is the flow diagram for the bucket circuit of the Surplus Center regen valve that I linked to before:

Each box is a different position for the bucket circuit in the valve, the top two connections are the lines to the bucket (A and B) The bottom two are the pressure inlet (P, on the left and T, on the right).
Note that in the far left box (regen dump), the P, A and B lines are connected.

Here is the flow diagram for the loader arm circuit of the Surplus Center regen valve that I linked to before:

Each box is a different position for the bucket circuit in the valve, the top two connections are the lines to the loader lift cylinders (A and B) The bottom two are the pressure inlet (P, on the left and T, on the right).
Note that in the far left box (float), the P, T, A and B lines are connected, this is different from the regen circuit and is why the loader will lower in float vs raising.
In theory, if you swapped the lines for the loader lift and bucket dump circuits, it would lift with regen dump position if the pressure difference was enough.
As for the pressure differential, with a 2" bore, 1" rod cylinder and 2000PSI fluid, in regen mode, you would have 4712# trying to retract the cylinder and 6283# trying to extend the cylinder per the Surplus Center calculator at: Surplus Center

So, each cylinder would be trying to dump with 1571# of force.

Aaron Z

 

[JWR]

Yes, I do have regen dump on my tractor. I don't understand your test. If the loader lift (e.g. frame control) is in float it just lowers to the ground until the bucket stops it and sits there. One does not move the loader to put the bucket into regen dump position but rather you move the joystick to the far right (position 6 in the diagram below) beyond the normal "force downward" position. The bucket stops of course when it lies flat on the ground. It got there by gravity. It won't lift the tractor front up at all since the loader valve (in regen dump) is allowing rapid flow back to the reservoir and not affecting the movement of the curl/dump cylinders. The bucket will not force the tip downward in regen position. It could not lift the front end anyway in the test you suggested because the loader frame was to be in float mode so the loader frame would just rise, not the tractor, if additional dumping motion happened in the regen mode.

I SAY all that as if I'm on the thing, but my tractor is 300 miles away and I can't just go get on it. I travel to the farm once a month. I just know that is how it acts from having used it for the past 8 years. [I'll certainly do due diligence and run your test next time I am back there.] I hesitate to have all these folks bored with details of my situation but ...I'll try to be concise and tell it:

The original loader valve (NIMCO CV152) brand new, 2011, was defective such that one could not force the bucket tip downward regardless of control position. At least 2 other loader valves on MF 2650/60 series tractors new on the lot at a dealer had the same issue (he had sold a 3rd and it reportedly had the same issue.) On top of that, the AGCO depot level parts people sent the dealer a new CV152 which was put on my tractor replacing the original. It was bad with the exact same disease. AGCO gave the dealer little/no help, the dealer was baffled, and with me only there once a month it was ... a mess. Finally I contacted NIMCO myself, their engr told me "they had let a few bad ones out the door" and he sent me a kit to replace the spool control assembly out on the end of the loader valve. I fixed the thing myself that way. Had to do with cumulative tolerances out along the length of the spools. After that I can lift the front end off the ground using dump position but not regen dump of course.

Here is the applicable page from the operator's manual:




Notice that in position 5 the bucket dumps and...hydraulic pressure forces the cutting edge down. In position 6 (the regenerative position) the weight of the bucket and contents dumps potentially faster than it would under normal hydraulic pressure and (since the hyd fluid is bypassing everything and going straight back to the reservoir, cavitation is prevented.) If you had a very heavy bucket load and went into dump as hard as you could go WITH hydraulic pressure, the load would in effect be sucking fluid too fast through the cylinder leaving air space behind (hydraulic flow not keeping up with the drop rate) and making for potential cavitation damage over time. So if you want to do a lot of heavy loader work dumping as quickly as you can -- go to the regen position and let gravity do the faster dumping. That's the way I read the manual and that is my understanding.

I hasten to say this situation with an 81 horse 2660 and a DL250 loader is probably different from the behavior of a DL95 or whatever the OP is using on his GC1700. Intuitively I would think that the GC1700 series is much less likely to have this more complicated type loader valve.

You lose me in the higher and lower pressure discussion. So far as I know there is only one high pressure level from the pump, controlled at that level by a relief valve, and fed to where ever the control valve directs it.