Regarding 3rd function valve sticking

[brocas]

I had my dealer install the 3rd function valve on my L3940 to operate a grapple. This was based on the advice of a lot of people that claimed (guessed perhaps:confused2 that its beter than a selector valve.

When I first tried it with my grapple, the speed was too high (to the point where movements were so sudden it looked like the grapple would fly off!).

I think the problem was amplified because the grapple has only a single small cylinder. So, I decided to add flow control valves to restrict the flow and slow the thing down.

The flow control valves definetely control the speed. But, when the speed is reduced to a level that I think is "right", the dreaded 3rd function valve sticking shows up.

I thought that this sticking was somehow related to the flow control valves but from previous thread looks like the 3rd function valve may have issues with sticking.

I still leave the flow control valves on and turn then until there is no sticking but the resulting speed is still too high (but much better than with no control at all).

I was really hoping that the 3rd function valve would work for me, but at least in this applicaation for me, not only do I not get "feathering" but I also get sudden movements, so very little to no control.

Needless to say, I'm looking for other options.

I hope this helps someone thinking of addiong this valve, it may not work well for you application.

 

[Whitnel]

Man this sucks. You are the third person in the last few days to mention this. I was looking foward to the third function valve. It seemed better than the other brands as you could use it at the same time with the other loader functions.

 

[brocas]

Yes I think this valve is really not suited to operate a grapple. On/OFF is simply too fast, I think even with two large cylinders. I suspected this, my plan B was to add the flow control valves (even though this is not an ideal solution since the releif valve is dumping the "extra" flow). But with the valve sticking, this is no go.

Too bad I'm not a hydraulics expert because I suspect there is a simple solution.

What I would like is a HI/LOW switch to control hydraulic fluid flow. This would be great for all the hydraulics when you want to switch from speed to precision. I cant believe this would be that hard to accomplish :licking:.

 

[Whitnel]

What about putting a reducer on the hydraulic line. The would slow the flow down and that would slow down the cylinder.

 

[teg]

What size hoses are you using?

I wonder if moving the flow control near the grapple would help?

 

[David_Kb7uns]

Other than my trigger switch failing I do not have any problems with the WR Long valve on the L3130, think I would try that one, and I think it may be cheaper.

David Kb7uns

 

[Sockwell]

I also have the WR Long. In fact, when I bought the L3240, the Kubota dealer recommended it over the factory Third Function. Mine is used solely for a Construction Attachments grapple and there have been no problems at all. I liked it enough I had them move it to my newer Kubota.

 

[J_J]

With a high volume valve, and a small cyl, you can expect fast action. About the only way to decrease the speed is to reduce volume by restrictors, diverting some of the flow, and use of the feather ability. . The solenoid valve is full on or or off unless you want to add those proportional valves that only provide as much volume as needed.

Is your needle valve in front of the solenoid valve.

Option, install a larger cyl for more down force, and slower speed of activation.

 

[J_J]

A 2 in cyl ,1 in rod, 10 GPM, = 12.3 ips ext, and 16.3 ips retract.
-----------------------5 GPM = 6.1 ips extend---------8.2 retract ips

A 3 in cyl, 1 in rod, 10 GPM, = 5.4 ips extend----------------6.1ips retract
-----------------------5 GPM = 2.7 ips extend----------------3.1 ips retract

So volume and cyl size will affect the grapple speed.

 

[Rockgod]

Yes I think this valve is really not suited to operate a grapple. On/OFF is simply too fast, I think even with two large cylinders. I suspected this, my plan B was to add the flow control valves (even though this is not an ideal solution since the releif valve is dumping the "extra" flow). But with the valve sticking, this is no go.

With the two large cylinders (my grapple) the flow rate seemed to work well, not to fast not to slow just right.

I really hope kubota get this 3rd valve thing figured out.