Hydraulic lock valve issue

[Dadnatron]

I have a Chinese import articulated flail mower which has been working fine, but I have a new issue.

The hydraulic lock valve on the main 'raise/lower angle' cylinder began leaking and a fitting broke. I have always hated how this was setup, floating on nothing but the connections to the cylinder, but it was working, so I left it.

Apparently, the raising and lowering caused stress on the tubing connection just as it connected to the lock valve and when I was messing with it, it broke completely off. Basically, the connection is exactly like you see remaining connected. it is a metal connection to the cylinder, with a very short rubber hose (to allow for flex) then another metal connection leading to the valve. It is the connection right at the valve which broke.

Anyway, I need either another piece of the metal/rubber/metal connector to reattach or I need a completely different type of connection to better attach the lock valve to the cylinder.

Any ideas on either where to get another or how to connect it better/more stable? That valve just floats on the 2 connectors, as designed... its just not a GOOD design.

 

[Dave M7040]

That lock valve looks like a previous owner add on and not part of the original design.

Do you even need it with a cylinder in good condition?

Three point hitch hydraulics usually incorporate a relief valve and a safety valve. The relief valve limits how much you can pick up.
Once the load is lifted, the hydraulic fluid is lock in and the relief valve does nothing should you add more weight to a raised implement as an example.
.
The safety valve bleeds off pressure generated when a load is bouncing on the 3 pt hitch and its setting is much higher than the relief valve.
The safety valve is set using a fuel injector tester so not a do it yourself task.

Most loaders do NOT incorporate a safety valve. Often owners who add forks to their FEL end up breaking expensive parts because the added leverage generated by the forks has no where to go and things break.

I suggest you look at your articulating flail in the safe light.

Dave M7040

 

[Dadnatron]

Honestly, I don't know. It came like this from the factory. I am not sure whether the valve only locks or allows for the flail to 'float' after a given pressure is overcome.

I've never liked the connection for this reason, but whether or not I can simply do away with it is beyond my level of 'expertise'. The hoses connect directly to my tractor valve, so I would suspect they would hold pressure fine.

I'd love to toss it on the 'spare parts' shelf, but I certainly don't want to do that if it is integral in the safe function (ie, I won't tear it up) of the machine.

 

[Dave M7040]

Honestly, I don't know. It came like this from the factory. I am not sure whether the valve only locks or allows for the flail to 'float' after a given pressure is overcome.

I've never liked the connection for this reason, but whether or not I can simply do away with it is beyond my level of 'expertise'. The hoses connect directly to my tractor valve, so I would suspect they would hold pressure fine.

I'd love to toss it on the 'spare parts' shelf, but I certainly don't want to do that if it is integral in the safe function (ie, I won't tear it up) of the machine.

Do you have a manual you could post?

Dave M7040

 

[ovrszd]

Stuff like this bothers me. I'd have to build a bracket to securely hold the lock valve to the cylinder barrel. Maybe using some sort of barrel clamp with a flat bracket. Use the two holes thru the body of the valve?

As to the fittings. They appear to be standard stuff. Unscrew the fitting from the valve and the banjo bolt from the cylinder. Go to your friendly tractor dealership and find fittings that fit each end, eliminating the steel portion, building a short hose??

 

[Dadnatron]

Do you have a manual you could post?

Dave M7040

LOL.... HA HA HA HA ha ha ha ha .... heh.... Manual......

 

[ericm979]

I think it's either a pilot check valve or a crossover relief or maybe both combined in one. The hex sided things on each end look like adjustable relief valves. Those would (hopefully) prevent damage to the mower head from overpowering it with the hydraulics.

Pilot check valves would keep the cylinder from "bleeding down" due to leakage past the valve on the tractor. They are common on hydraulic 3pt top links. They don't allow float so if it floats then the valve doesn't have checks.

The fix would be to get new longer hoses made to run from the mystery valve to the cylinder. That would allow you to mount the valve solidly to the cylinder using hose clamps or a fabricated bracket. They spent the $$ to put it on so I would lean towards making it work rather than removing it.

 

[ericm979]

Here's one that has what looks like a check valve: VL-AGL Silver & Gold Ditch Bank Flail Mower |
This one touts a floating tilt and does not have a mystery valve on the tilt cylinder: VL-AGF Gold Ditch Bank Flail Mower |

The hoses for the mystery valve to the cylinder probably cost about the same or a little more than the fittings to remove it entirely and run your hoses directly to the cylinder.
OTOH if you have a float-capable remote valve, and the mystery valve is a check valve, removing it would get you float.

 

[Dadnatron]

The fix would be to get new longer hoses made to run from the mystery valve to the cylinder. That would allow you to mount the valve solidly to the cylinder using hose clamps or a fabricated bracket. They spent the $$ to put it on so I would lean towards making it work rather than removing it.

I tend to agree with you Eric.

The hoses are long enough that a cylinder mount would not be an issue. Clearance is the only issue, but I suspect I could position it somehow without too much difficulty. I'd just need to find/fab some brackets/clamps for the attachment.

I'm not sure why they used/needed the banjo bolts rather than just short hoses from the cylinder to the valve. Other than not actually mounting the valve somewhere, I don't really see the need for the bolts rather than just a short hose from the valve to the cylinder. If I clamped the valve to the cylinder and attached short hoses from the valve, do you see any reason it wouldn't work? (If physically I have clearance and slack for main hoses?)

 

[ericm979]

The banjos might act as flow reducers so the thing does not move too fast. It's a small diameter cylinder which would move fast if not restricted. If you run fittings into the threaded holes in the cylinder you could put reducers in the fittings (the ones that are basically washers with tiny holes which go inside fittings) or add a needle valve or valves to the circuit somewhere. You could even put that on the tractor end of the hose by the quick connect since room is tight on the mower.