GC1700 series fast dump loader function??

[bartjoebob]

Both the manual and sticker next to the loader joystick indicate there is a fast dump mode for the loader bucket on a new GC1705. I have no trouble with float mode but cannot seem to get the bucket to tip any faster than a slow roll. I thought this might be more like a release and gravity dump. Any thoughts on this? Or is this function not really that substantial with a GC series running a DL95 loader?

 

[coldsteelva]

It depends on how much weight you're trying to tip out/dump, plus the hydraulic fluid still needs to move in order for the cylinder to extend using the weight of the load to 'pull' the bucket. I agree that it isn't an insta-dump, but I think the return line ID is the limiting factor.

 

[teg]

I have that "feature" on my tractor... like you, I wasn't impressed.

 

[frugalangler]

I've used it - it definitely is load dependent, empty bucket doesn't dump much faster, but full of dirt or gravel and it will definitely spill it's load quicker, but not immediately.

 

[JWR]

I have that feature on a MF 2660 81 horse tractor. Pure pain in the butt and of no real value. Something to add complexity and haunt you eventually. First off, it just allows a gravity dump if you have a heavy bucket load to go faster than it would under power. Whoopeee. Apparently the feature was intended for commercial users of larger tractors where time equals money and someone probably lobbied for the feature (or more likely the foolish marketing people THOUGHT someone wanted it.) In any case the primary result is a more complex and expensive loader valve which is finicky to adjust and more prone to failure. I have been so P.O.'d at that loader valve ... long story involving not only a bad original from the factory but another bad one from AGCO depot parts via a dealer. Would not allow forcing the bucket tip down in curl. Eventually fixed it myself using a kit from the valve manufacturer (Nimco.) Over the next 3yrs the loader valve developed complete slowdown and "won't work at all" until the oil gets hot. That is cause for a new set of seals which a dealer says will cure the issue. In my book the BEST loader valve is the simplest one, typical of small to medium sized farm tractors that has NO special features, NO fast dump and just does what it is told to do. I'm literally ready to throw this $1100 loader valve away and put on a simple one if the new seals don't solve the problems.

 

[Snobdds]

It seems to work really well on my 1710. It's not just the normal move to the right of the loader control stick. It really has to be as far right as the loader control stick will go. It works if there is a load in the bucket or not.

 

[JWR]

It seems to work really well on my 1710. It's not just the normal move to the right of the loader control stick. It really has to be as far right as the loader control stick will go. It works if there is a load in the bucket or not.

I realize that is how it operates (mine did too, just not very well and got worse.) The reason it works in the "far right" joystick position regardless of whether you have a load in the bucket is that the bucket itself is forward of the pivot point for curl and has enough weight of its' own to cause gravity curl. I just meant that havng a good load in the bucket makes that curl fast and that (fast dump) was the purpose of the feature.

Glad your's work's well.

 

[AxleHub]

Just a reminder to readers, that JWR has and is referring to his 2660 81 HP tractor, which is a much different unit than a gc1700 series.

 

[jeepcj7]

It was once explained to me like this: the original purpose of "Fast Dump" was not fast dump at all, it was to keep the bucket cylinders from cavitating when dumping a loaded bucket at low rpm's. By that I mean the bucket cylinders could extend faster than the pump could replenish the oil in the cylinder sucking air into the cylinder from the reservoir. As a benefit, the bucket would actually dump a little faster hence the term "fast dump" (sounds better than "cavitation prevention device"). It does this by opening a passage in the loader valve between the rod and barrel ends of the lift cylinders. Now concerning the GC, dump time with a loaded bucket at typical operating speed (say around 1800 pm) is about 4 seconds. Fast dump makes dumping a loaded bucket about 20% faster - so dump time is now about 3.2 seconds. Personally I will never notice 0.8 seconds difference in dump time, but i do appreciate the fact that it helps to keep the bucket cylinders from cavitating.

 

[Fiziksgeek]

Let's be honest here, for all intense purposes, there is no fast dump on the GC1700 loaders.

 

[wakeshredder]

I think the fast dump is more of a "float". Basically it opens the center of the valves and the feed/return. Like like the loader boom float, with no power on the cylinders and nothing holding the fluid, it lets gravity do it's thing. Of course, you'll still be limited by the fluid in the lines free movement. So, heavy load with fast dump, is really fast. Empty bucket, not so much.

 

[MaineGuy1]

Yeah, I'm not impressed with mine even with a loaded bucket. It doesn't matter though because I think I know it's purpose and it is not just for "fast" dump. Like others have said I think it just unloads the cylinders and this may help in certain situations.

 

[cdaigle430]

Mine works well, I just double tap the joystick to the left.

 

[atsah]

Mine works well empty or full, hold it all the way to the right and it dumps faster, it's not a float of any kind.

 

[JWR]

On a larger loader, my DL250 on a MF2660 tractor, the fast dump feature is certainly there and to my knowledge IS the same as moving into float for the dump. There really is no other way for it to get "fast."

Atsah: How does the loader dump faster than normal hydraulic driven speed other than by going into float and using the gravity of the bucket load?

While we are on this topic: I detest these more complicated loader valves !! Nothing but trouble going somewhere to happen. ESPECIALLY on machines like the GC1700 series the more complex loader valve does nothing but drive the price higher and invite trouble where the feature was unjustified in the first place. For non-commercial users like me the benefits are zero and the drawbacks are bad. It causes loader valves to cost over $1000 for starters. Mine was flaky/unreliable and replaced twice before people figured out the AGCO parts stock was ALSO bad. The extra fast dump (and anything other than simple joystick operation) require complexity in the manufacture as well as operation and failure modes. I would pay extra to get rid of the $%^&* thing and go to a simple loader valve like those generally found on the smaller plain tractors like the DL125 loader typically has on a tractor like a MF1736 or older similar ones.

 

[atsah]

Atsah: How does the loader dump faster than normal hydraulic driven speed other than by going into float and using the gravity of the bucket load?

Don''t know but if I put the bucket against a snow bank and uncurl it, it does it quickly and will pick up the front of the tractor doing so.

 

[JWR]

Don''t know but if I put the bucket against a snow bank and uncurl it, it does it quickly and will pick up the front of the tractor doing so.

Sorry, but the physics of the circumstance does not support your observation. The fact that it "picks up the front of the tractor doing so" proves that the bucket dumping motion is hydraulic driven. There is nothing about a quick dump feature that provides more hydraulic pressure nor more sudden volume of hydraulic fluid flow nor anything else (other than gravity) to produce the motion. Just does not happen. In fact, the bucket being driven downward under hydraulic pressure proves you were NOT in the quick dump mode at that point (!) You were in the normal dump position of the loader valve.

It is POSSIBLE that someone makes a loader valve that is a "flow control valve" in traditional terminology and increases flow to the full available amount if you move the lever further to the right. Never heard of such a thing but could be. IF IT IS that then the loader is simply under performing until the control is forced further to the right. Very unlikely.

 

[aczlan]

Sorry, but the physics of the circumstance does not support your observation. The fact that it "picks up the front of the tractor doing so" proves that the bucket dumping motion is hydraulic driven. There is nothing about a quick dump feature that provides more hydraulic pressure nor more sudden volume of hydraulic fluid flow nor anything else (other than gravity) to produce the motion. Just does not happen. In fact, the bucket being driven downward under hydraulic pressure proves you were NOT in the quick dump mode at that point (!) You were in the normal dump position of the loader valve.

It is POSSIBLE that someone makes a loader valve that is a "flow control valve" in traditional terminology and increases flow to the full available amount if you move the lever further to the right. Never heard of such a thing but could be. IF IT IS that then the loader is simply under performing until the control is forced further to the right. Very unlikely.

Fast dump or regen dump ties both of the cylinder lines and high pressure in from the pump together. It causes it to dump because the surface area of the rod side of the cylinder is smaller than the surface area of the base side of the cylinder.
You gain speed compared to a "regular" dump but you lose force because you are pressurizing both sides of the cylinder...
That is why it doesn't work with a motor, or a truck snowplow that uses two single acting cylinders.

Aaron Z

 

[aczlan]

I have that feature on a MF 2660 81 horse tractor. Pure pain in the butt and of no real value. Something to add complexity and haunt you eventually. First off, it just allows a gravity dump if you have a heavy bucket load to go faster than it would under power. Whoopeee. Apparently the feature was intended for commercial users of larger tractors where time equals money and someone probably lobbied for the feature (or more likely the foolish marketing people THOUGHT someone wanted it.) In any case the primary result is a more complex and expensive loader valve which is finicky to adjust and more prone to failure. I have been so P.O.'d at that loader valve ... long story involving not only a bad original from the factory but another bad one from AGCO depot parts via a dealer. Would not allow forcing the bucket tip down in curl. Eventually fixed it myself using a kit from the valve manufacturer (Nimco.) Over the next 3yrs the loader valve developed complete slowdown and "won't work at all" until the oil gets hot. That is cause for a new set of seals which a dealer says will cure the issue. In my book the BEST loader valve is the simplest one, typical of small to medium sized farm tractors that has NO special features, NO fast dump and just does what it is told to do. I'm literally ready to throw this $1100 loader valve away and put on a simple one if the new seals don't solve the problems.

Surplus Center will sell you a valve that you can choose to use regen, or not for under $300: 2 Spool Compact 1 GPM Joystick Control Valve | Directional Control Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com

Aaron Z

 

[frugalangler]

Sorry, but the physics of the circumstance does not support your observation. The fact that it "picks up the front of the tractor doing so" proves that the bucket dumping motion is hydraulic driven. There is nothing about a quick dump feature that provides more hydraulic pressure nor more sudden volume of hydraulic fluid flow nor anything else (other than gravity) to produce the motion. Just does not happen. In fact, the bucket being driven downward under hydraulic pressure proves you were NOT in the quick dump mode at that point (!) You were in the normal dump position of the loader valve.

It is POSSIBLE that someone makes a loader valve that is a "flow control valve" in traditional terminology and increases flow to the full available amount if you move the lever further to the right. Never heard of such a thing but could be. IF IT IS that then the loader is simply under performing until the control is forced further to the right. Very unlikely.

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!