FEL 3 way & 4way valve

[jrlichina]

The standard dump circuit is regenerative on both valves which means it allows fluid to flow on both sides on the cylinder. Since the rod side has less surface area it gets over powered by the other side. This allows for a more controled dumping of the bucket. If you push the lever all the way to the right which is the "fast dump" on a 4 way valve it only powers the one side of the cylinder for faster dumping. If you had a 3 way valve on a front blade setup you would only be able to angle it in one direction.

 

[kevinj]

</font><font color="blue" class="small">( If you had a 3 way valve on a front blade setup you would only be able to angle it in one direction. )</font> So you are saying that you can run a bucket cylinder both ways but not a blade angle cylinder ???????? The bucket cylinder is powered both ways just like the lift arms.

 

[JacknCoke]

I work for a Kubota dealer so I hope I can shed some light on this topic. Both the 3&4 way vavles mount the same way on the tractors. Visually they look almost identical (the end caps on the 4 way are the same length on the 3 way one is shorter than the other) If you dont have any front implements then both vavles stay on the FEL if FEL is removed from tractor by means of the quick detach pins . Now if you have a snow blower,angle blade, or sweeper for the front then removal of the loader is different because the upright w/vavle needs to stay attached.

The reason 3 way vavle does not work with these front implements is because it has a regenerative circuit (R.C.)which is different from the old vavles. When you dump your bucket, the hyd. oil on the rod end leaves the cylinder faster than the vavle can fill the base end of the cylinder (especially true when bucket is full as gravity makes it dump faster)So you end up with is a loose bucket and usually a slight lag when you go to curl back. So the new vavles with R.C., regenerate the oil from the rod end into the base end when you dump the bucket which prevents lag and loose bucket.The ports on the vavle are specific as to which end of the cylinder they go to (rod end or base end) If you dont believe me try swapping the hoses at the vavle (quick couplers) and you will see that the loader will lock up. So this type of vavle can not run hyd. motors (only one direction) or it can not work with cylinders that are moving in the opposite direction like on the angle blade (one is going in as the other is going out).

The reason that the 4 way vavle is needed is because in the fast dump position there is no regenerative circuit.

Kevinj. I do agree that this does not follow what we have always been taught about Hyd vavles but this is how it works now in the new and improved world. Ha-Ha. I also think Kubota should just use the 4 ways from the begining and nobody would have to worry about it.

I hope this helps. J.D. /forums/images/graemlins/cool.gif

 

[kevinj]

</font><font color="blue" class="small">( The reason 3 way vavle does not work with these front implements is because it has a regenerative circuit (R.C.)which is different from the old vavles. When you dump your bucket, the hyd. oil on the rod end leaves the cylinder faster than the vavle can fill the base end of the cylinder (especially true when bucket is full as gravity makes it dump faster)So you end up with is a loose bucket and usually a slight lag when you go to curl back. So the new vavles with R.C., regenerate the oil from the rod end into the base end when you dump the bucket which prevents lag and loose bucket. )</font> So on the Kubota blade the cylinders are one way like a truck plow ???? If it was two way then it could work like a bucket, I talked to an old hydraulics guy over the weekend and he says the quick dump valves also have a relief in the to allow blade pivot if you strike an object (breakaway relief). </font><font color="blue" class="small">( The reason that the 4 way vavle is needed is because in the fast dump position there is no regenerative circuit.
)</font> Based on what you are saying the blade angle would have to trip a relief to swing as the quick dump only opens to the right and not to the left on the control.

Thanks for the input, I do not have a blade or loader on mine so I can't experiment with the hoses. My dealer does not seem to understand the operation himself.

 

[Deerlope]

Thank you for the ifo on the 4/way valve. It all makes since now because the snowblow has a hyd motor to turn the shute. Sure wish that my dealer had known this and had explained it so well.

 

[kevinj]

Given the fact that the 3 way is a regen I can see the problem. It seems that it is technechly a 4 way with regen for the bucket on one spool. It DOES allow for 4 way operation of the loader hydraulics. So then is the 4 way a plain valve on both spools and the fast dump is the regen circuit ?? I been trying to get this answered since February when I got my BX. I called Husco today and they gave me a different spin on things. I tried a third dealer in my area he basicly said: Kubota says you need 4 way due to hydraulic motor chutes on some blowers. He did not feel that it was important to know how it worked. ( Guess where i will not take my tractor ! ) So it seems that the bucket spool off a 3 way would run a tilt cylinder if properly connected. I do agree that they should just have the one valve and be done with it.

 

[JacknCoke]

I forgot to mention that the 4way comes with quick couplers between the vavle and loader so that that loader can be removed while the vavle stays on tractor or you can remove the whole thing by removing the quick pins and main quick couplers. The 3way does not come with couplers between loader and vavle.

The cylinders on the angle blade are double acting. The reason they will not work with regen is because when one is pushing rod out and the other is pulling rod in. Which will lock up with a regen vavle.

J.D.

 

[kevinj]

So the blade angle is using 2 double acting cylinders ??? I think I see the issue now. My dealer has not installed a blade and could not tell me the arrangement. I understand that the blade for a bx1500 is manual angle so it seems silly to sell us the expensive valve when we only need one spool to raise, lower and float.

 

[cheekme]

J.D. My L35 definitely has the 3-way valve based on your end cap description (the left one is shorter than right as viewed from RH side of tractor). If I move the bucket dump lever all the way to the stop I get the fast dump but it has a hesitation. Once there I can shake the bucket and remove sticky material. My problem is that my bucket flops badly when trying to backdrag. Are you saying the RC (regen) on the newer valves prevents this flopping? My machine was built in '99 and I'm the second owner. I thought I just had air in the head end (base) of the cylinder but maybe what I see is "normal" but it sure is a pain sometimes. Also do you know if Husco is the valve supplier.

Mike