New Holland 1620 / 7108 loader troubles.

[klem531]

Please help!!! I'm having an "issue" with the bucket curl circuit on my loader. The story goes like this....I just purchased a New Holland 716b snow thrower for my tractor. Found her on craigslist and drove 750 mi round trip to get her. (it was a really good deal).:licking: Anyway, my loader has been working fine, no issue's or hicup's whatsoever. I took the loader off this weekend and mounted the snow thrower, connected the raise/ lower cylinder on the snow thrower to the loader raise / lower circuit and works perfectly. It will even raise the front of the tractor off the ground... I then connected the hydraulic chute motor to the bucket curl circuit and it rotates fine in one direction but not the other. I immediately assumed there was an issue with the motor so I connected the motor to the loader raise / lower circuit and it works fine! Rotates in both directions at light speed. Ok so that eliminates the motor on the chute being suspect. I then connected the the Raise / Lower cylinder on the snow thrower to the bucket curl circuit and I have the same problem. It will raise fine and it will lower but I cannot get any down pressure. If I hold the LCV open the tractor labors like normal but there's just not enough pressure to raise the front of the tractor....Not even a little I did a forum search on here and found a guy who's handle is Hyndsight and he had a similar issue which turned out to be a bad quick coupler on his hydraulics. SO what I did was I swapped the quick couplers on my remote's, in other words, I took the two from the curl circuit and put em on the raise / lower circuit and vise versa. I plugged everything back in and I still have the same problem on the curl circuit.:banghead: Could I have a bad LCV??? Just not really sure what to try next. Any insight is greatly appreciated.:thumbsup:

 

[RickB]

Search renerative spool and non-regenerative spool. Your current loader valve bucket circuit spool won't do what you want it to.

 

[J_J]

On some loader valves, regen is located in the first part of the valve, and if that is the case, one of the work ports is closed off for regen to occur.

If regen is located in the second part of lever travel, just don't go into regen.

Another option is to spring load the chute and use the side of the valve that will allow chute movement.

I.E. spring load the chute to the right and use the hyd motor to swing it to the left.

 

[klem531]

Ok fella's now I understand! I did like ya said and searched Regenerative and found this excellent explanation Regen is a "feature" of most modern FEL (Front End Loader) valves, it's on the Dump (joystick far right) circuit, and is also referred to as "Fast Dump". The reason it is nice to have is that without it, the weight of a filled bucket can actually "pull" the bucket down faster then the fluid can enter the other side of the cylinder, this will create a air pocket and give the bucket a "floppy" feeling until the joystick is held in the dump mode a few seconds to refill the cylinder pushing the air past the seals. So we add "regen" or "regenerative" function to the valve.*

Regen solves this problem by actually filling both sides of the cylinder at the same time with hydraulic fluid. But how will that work you might ask? Well, because there is more volume on the side of the cylinder that extends it since the rod is taking up space in the other side, it "overpowers" the rod side and lets the cylinder extend-thereby dumping the bucket. So since now both sides of the cylinder are "pressurized", the air pocket can not develop, eliminating the "floppy" bucket syndrome. One other added bonus is that the bucket actually dumps faster due to the higher flow rate required to do all this, that's why it's referred to as "fast dump" sometimes.

So, now you may be asking "This is cool and all that, but why do I need to know about it??" The answer to that is simple, if you ever try to run a snow plow with two SA (single acting) cylinders, or a cylinder that drives a chute rotator on a snowblower you will soon find out that they won't work if you push the joystick to far right in the regen mode. The plow won't work because since both lines are pressurized-both cylinders will be trying to extend at the same time binding everything up. The rotator won't work because there is no weight pushing the cylinder closed like there is on the loader.

 

[klem531]

Thanks a million for everyone's help! This brings me to my next question... I wonder how a dealer would have set this up if I were to have bought it new with a snow thrower? Would they have installed a different valve for schute rotation? Used a spring? Or is the best way just to use the bucket curl circuit for the up / down since I guess I don't really need down pressure with a blower anyway.?

 

[RickB]

We swapped out the bucket function spool for a non-regenerative type. Pretty sure that spool is NLA now. You would need to know whether your valve is a Zexel or Kayaba brand to check availability of that non-regen spool. Used to be north of $300.

 

[klem531]

RickB, I think I'll muttle by for that kinda money lol.It should work just fine rrunning the up /down off the bucket circuit. Thanks again to everyone for the input. You guys are some real smart fellers. :thumbsup:

 

[klem531]

We swapped out the bucket function spool for a non-regenerative type. Pretty sure that spool is NLA now. You would need to know whether your valve is a Zexel or Kayaba brand to check availability of that non-regen spool. Used to be north of $300.

RickB, would you just swap the spool back when you wanted to use the loader or did you just delete the regen function all together?

 

[J_J]

Regen is just a fast dump, so if you don't need the fast dump, don't use it.

 

[klem531]

J_J. I thought that the regen also prevented the load in the bucket from forcing the fluid out faster than it could be pumped in? At least that's what I thought I read in the post I found.