Stabilizer safety control valve issue -Ford New Holland

Hi,

I have a Ford New Holland 675E that has a stabilizer safety control valve on each of the backhoe stabilizers. I believe the valve is there to prevent the stabilizer from sagging if the hydraulic system has a failure away from the cylinder.

One of the stabilizers recently started sagging, and I think this block is the problem because it vibrates quite a bit in a way that the good stabilizer does not.

Specifically, when I put the stabilizer down it will lift the machine, but then as soon as I let off of the control lever the machine will settle back down on the wheels.

I know it could also be an issue with the seal inside the cylinder, but I wonder about that for a few reasons:
- This started happening suddenly, it's not like it used to gradually sink and now sinks quickly. Now the machine will settle back to the ground in a few seconds
- When I hold my hand on the lever it will stay in the air. I guess this means the flow could just be more than the leak though?

I attached a photo here of the valve block on the stabilizer cylinder. I tried googling for the part number but came up empty.

So my questions are:
1 - Does this sound like a good theory that this safety block is the problem?
2 - Is it serviceable in any way?
3 - What are these things called to find a new part?

First time posting but these forums have saved me in the past. Thanks for any help!

Your photo did not load. As I understand, newbies aren't allowed to post pics on this site.

Does the valve in question look like #3 in this image? If so, NH doesn't show anything as being serviceable inside, but that shouldn't
prevent you from taking it apart to see if you have a blown o-ring or similar issue.
Valve

Hi,

Thanks for posting that diagram! #3 in the diagram that you posted is indeed the right part.

At nearly $500 for a new one I'm hesitant to open it up not really knowing what to expect or how it works.

Do you have any more general thoughts on whether I'm on the right track here or how to approach this?

Us old country boys call them load locks. Not much in there but a check ball or two and a spring or two. Don't rule out a blown packing on the piston. If you are afraid to tackle it , take it to a good hydraulic shop and let them disassemble it.

Something you could try would be to swap this valve with the one from the other side, since the parts book shows them as being identical. If
the problem follows you to the other side, the valve is bad. If the problem stays on the original side, you likely have a bad packing in the
cylinder.

Thanks, that's a very simple and good suggestion to switch them. I'll give it a try.

Yup, sounds like a simple stop valve as [u:7cb49b4ded]welding man[/u:7cb49b4ded] said.


I always called them stop valves. They keep the load from falling if pressure is lost on the line feeding the cylinder, as in a ruptured hose. Under normal circumstances they allow pressure into and out of the cylinder, but will block fluid from leaving the cylinder (getting past the stop valve) if there is no pressure on the other side of the valve. So ..... under normal operating conditions this valve [u:7cb49b4ded][b:7cb49b4ded][i:7cb49b4ded]should be[/i:7cb49b4ded][/b:7cb49b4ded][/u:7cb49b4ded] letting oil flow by in either direction. In other words, it is not blocking oil flow either way, so there is no leaking by.

Personally never saw them on stabilizers. I usually see them on large lift cylinders

I too would suspect a leaking piston seal in the hydraulic cylinder. Simple to check. Google end-of-stroke bypass test.

This post was edited by jimtrs on 09/09/2021 at 09:45 am.

One more thought - I realized this started happening soon after replacing all the fluid filters. I've ran the machine about 20 hours since then and used the stabilizer dozens of times so I would have thought any air would be purged, but perhaps this is a problem?

Hello again,

So I did the bypass test and it seems that the cylinder is good. I strained the engine against it for 30 seconds and it didn't move at all with another person outside watching the piston.

I also tried hooking up the cylinder without the load block in the circuit and it still sagged. So then I switched the load blocks from one side to the other, and the same side still sagged.

This makes me think that the problem is actually in the cab somewhere because switching the load blocks did not switch the side with the problem and the cylinder passed the bypass test.

Any ideas what to look at next? I was thinking maybe there's some sort of pressure relief that somehow got messed up...but not sure if that's a thing?

Thanks again!!