Help with valve and cylinder problem

[Scott65]

Hey guys, kinda in a pinch here. I'm hoping someone can shed some light. I've pre-ordered all of my parts to make a grapple on the front of my Kubota L3301. All is rigged up but when I push the valve in either direction, it just locks up the cylinder and won't operate the grapple in either direction. The power beyond is all hooked up correctly because I have all other functions (loader and 3 point). And the pump isn't laboring when all is in neutral. It bogs down when I attempt to operate the valve, just like when the loader is maxed out, and fluid comes through the "return to tank" line as it should when over-pressurized.

This may be simple: I contacted Baileys several months ago and purchased the valve that they suggested. I never thought twice until right now. I just looked it back up on their website and instead of open center, its labeled as tandem center. Research shows that when in neutral, it holds pressure in the 2 work lines. But I don't find anything about what it does when you activate the valve. Is it that its applying pressure to one work port, but dead-heading it in the other, therefor blocking the fluid return path for the cylinder to operate?

And if this is the problem, is there a way to fix it without replacing the valve? My thought was to try drilling a hole in the power beyond plug to allow the "tank" pressure to bleed into the power beyond port, since loosening that was the only way to relieve the pressure in the ram. I'm sure this isn't the correct way, but will it work? I'm stuck, I need this thing working, and I don't have any other sorts of fittings to replumb it at the moment.


In case anyone needs to know, its a Chief Directional control valve, 4 way, 3 position.
It has 2 work ports, A and B. The inlet port, and tank port, labeled T. Then I was instructed to pull the plug from the N port, install it in the T port, and put the optional Power Beyond adapter back in the N port, and hook my "out" line to that, going to the block underneath the tractor and back to the 3-point

 

[ovrszd]

you're way over my head. Hopefully JJ will chime in soon and shed some light. Sorry for your troubles.

 

[Scott65]

Ok, I think I've figured out what's going on. I still don't know if its right or not, so input is definitely still welcome.

I'm no hydro expert so I'm sure my terminology isn't correct. But to explain this, I'll say that my understanding of the circuit is this: You have pressure coming into the valve, and going back out through PB. When directed in the valve, pressure is diverted to one work port or the other, then springs back to the free-flowing position. When pressure is pushed into one chamber of the cylinder, it must be released in the opposing chamber to allow ram movement. So it would seem that this valve will not dump the fluid from the non-working port into the PB circuit. I believe I need to "T" into the overflow Tank connection that the pressure relief uses and attach the Tank port on the valve to this. So in essence, the supply and PB paths keep pressurized flow going to the 3-point, while the Tank port simply dumps the unpressurized "relief flow" from the dead side of the cylinder directly back to the tank. Does this sound accurate? And does is sound right that the valve was designed this way? Or did I get a bad valve? I've removed the plug and confirmed that this is, in fact, how the flow is going and it allows the ram to operate this way. But that doesn't mean it was supposed to.

What risk is there of T-ing into this return path? I hope its never pressurized, seems it could cause the 3rd function to go haywire. I'm off the Tractor Supply in hopes of them having a T and a few fittings needed to try this. I'll check back upon return to the shop in case I need to stop what I'm attempting.

Thanks in advance

 

[TomSeller]

This description from a google search would indicate you should be fine with a tandem valve, the only difference being in neutral float

==========
TANDEM CENTER VALVES
Tandem center valves when in a neutral position by passes the flow of hydraulic oil to the return line. This is used to hold the cylinder/piston in position with no load on the pumps. When this system is the pump is running constantly to keep a ready supply of hydraulic oil, but as long as the cylinder/piston is not in operation the pump is working under no pressure or load. This system keeps wear and tear on the pump down to a minimum.

OPEN CENTER VALVES
Open center valves are the same as the tandem center, except that in the neutral position all lines are connected back to the reservoir. The primary use of this system is to prevent "shock" loading when the valve is placed in neutral. This takes pressure off the motor. This system is used in situations where the operating device needs to be moved by hand.
==========

It almost sounds like your tank line setup is not functioning and the fluid can't get out of the cylinders back to the tank

 

[TomSeller]

. When pressure is pushed into one chamber of the cylinder, it must be released in the opposing chamber to allow ram movement. So it would seem that this valve will not dump the fluid from the non-working port into the PB circuit.

I believe it would dump to the Tank return port, not the PB port. You do have 5 hoses connected, correct? IN, PB, Tank return, A and B? Ignore one set of cylinder lines in the attached. Aux is Power Beyond in this diagram

 

[TomSeller]

In case anyone needs to know, its a Chief Directional control valve, 4 way, 3 position.
It has 2 work ports, A and B. The inlet port, and tank port, labeled T. Then I was instructed to pull the plug from the N port, install it in the T port, and put the optional Power Beyond adapter back in the N port, and hook my "out" line to that, going to the block underneath the tractor and back to the 3-point

in looking back at your description, f your T (tank return) has a plug in it, that is your problem. You need a line from that port to the tank. You can Tee it in anywhere.

 

[J_J]

If you are using a valve with PB, you will have 7 hoses.

IN port

OUT port

PB port.

4 work ports.

All tank ports should go to tank, as that is low pressure and the OUT port can not handle high pressure.

A valve PB port connects to the next valve IN port.

You can tee all your tank lines.

 

[Scott65]

Thanks for all the responses guys! I'm only using a single spool valve at the moment. When I wrote the first post, I only had 4 lines. 2 work ports, in, and PB. The valve came with 5 ports, the PB port had a plug in it. I also ordered the extra PB adapter. I emailed Bailey because the valve didn't have any instructions or anything to point out which line was which. In the email I was instructed to take the plug out of the N port, put it in the T port, and install the PB plumbing in place of the N plugged port.

So I've learned now that instead of plugging the T port, I have to run another hose to the tank plumbing coming from the pressure relief output side of the loader valve. Naturally, nobody was open that had the right fittings to take place of that plug. So I'll be disassembling all of my grapple stuff so I can run the tractor and load it back up to take it home. My home is 30 miles from the shop. Yuck, how aggravating. Hopefully somebody will be open tomorrow. All I lack is one #10 O-ring elbow.

 

[TomSeller]

Thanks for all the responses guys! I'm only using a single spool valve at the moment. When I wrote the first post, I only had 4 lines. 2 work ports, in, and PB. The valve came with 5 ports, the PB port had a plug in it. I also ordered the extra PB adapter. I emailed Bailey because the valve didn't have any instructions or anything to point out which line was which. In the email I was instructed to take the plug out of the N port, put it in the T port, and install the PB plumbing in place of the N plugged port.

So I've learned now that instead of plugging the T port, I have to run another hose to the tank plumbing coming from the pressure relief output side of the loader valve. Naturally, nobody was open that had the right fittings to take place of that plug. So I'll be disassembling all of my grapple stuff so I can run the tractor and load it back up to take it home. My home is 30 miles from the shop. Yuck, how aggravating. Hopefully somebody will be open tomorrow. All I lack is one #10 O-ring elbow.

Sounds good, you just need the 5th hose teed into the tank line somewhere. Good luck. Post some pics of the grapple if you get a chance

 

[Scott65]

Certainly will. I wasn't able to take any today. My phone has been broken fora few days. As soon as I get one I'll post some up