Hydraulic Valve Question

[cabezaverde]

I have a 3 point hitch log splitter that uses the tractor hydraulic pump.

The control valve on the splitter is leaking pretty badly. Looks like I can pick up a new valve for around $100.

At that price, is it worth trying to have the existing valve rebuilt?

[Winger Ed.]

I'd get the shop manual for it.
You may be able to change a $5. seal or gasket on it your self.
Some old tractor websites sell rebuild kits for a lot of farm equipment.
Until you get off into the pumps, there isn't much to rebuilding hydraulic things except seals and 'O' rings.

If that's not practical, depending on how old it is, and how you value your time:
I'd probably get the rebuilt valve and be done with it in the much shorter time.

[rancher1913]

if you dont understand how hydraulics, especially how the control valve works internally, then replace the whole valve, you will be well ahead in lost time and aggravation. some valves are simple on off, some are multi function and divert the oil one way or another, just guessing but i imagine that valve does several operations.

[metricmonkeywrench]

I’m in the take it apart first and try to fix it camp, best case 20c o-ring, worst case new valve. You never know until you get in there.

Most of those circuits are fairly simple, dirt and metal chips are your worst enemy followed by age as seals harden and don’t hold tension as well.

A pix of the valve in question would be helpful

[megasupermagnum]

I can't answer to a log splitter specifically, but hydraulics as a whole use O-rings for seals. You likely only need to take off the offending end, and replace an O-ring that you can get from any hardware store for 30 cents.

[Mal Paso]

If the spool or the bore is warn replacing the seals is a waste of time. If it has had a lot of use or feels sloppy replace the valve. If it feels tight, no slop, replace the seals.

The spool is that round thing inside the valve body attached to the handle usually with a link. It slides in and out. Maybe a snap ring retaining it? The o rings are seated in grooves around the outside of the spool.

If the splitter has a detent for an automatic ram return, that is a bolt like assembly the screws into the side 90 degrees to the spool. That should be removed before the spool.

[megasupermagnum]

I had not even considered that you may mean leaking internally. If that is what you mean, no it is not worth rebuilding valves. If the spool is worn, the bore is worn, and often the oil has eroded another path anyway.

[cabezaverde]

Okay, figured I had nothing to lose taking the valve apart. Worst case I will have to buy a new one.

Here is what came out. I was surprised it only had one "O" ring. Thoughts on this?

262586

[metricmonkeywrench]

Don’t look too bad from what I can see, check the housing as well there may be an O-ring or two in it as well.

[Winger Ed.]

Looks OK.
There should be another oil seal or O ring at whatever place it was leaking, maybe the housing that shaft goes into.
I'd find the leaking part, change it, put it back together, and live happily ever after.

Then put the money you saved into the 'gunpowder and Whiskey' fund.

[megasupermagnum]

Again, never worked on a log splitter. My experience is in things like CNC, die casting machines, some large equipment. In that case, there are multiple O rings for multiple ports. Being as yours is a basic two way valve, and your ports are what the oil lines hook up to. I'm not surprised there is only a single o ring. The spool should seal on its own, and the one o ring only serves to keep oil from coming up the shaft. I doubt you will see an oil seal. You see oil seals in hydraulic cylinders, but that's mostly because they have to seal a moving piston rod. An o ring is a superior seal for a system that runs high pressures, and I'm sure even a log splitter can see 3000-4000 psi.

[gwrench]

Talk to the local bearing/industrial supply to get a replacement rubber parts. I'm fond of X rings rather than O rings. The profile obviously gives 2 sealing points and gives a spot where some grease can be put to keep everything happy and smooth. These parts are cheap so get the best you can find for less than lunch costs.

[megasupermagnum]

An X ring works great for pivoting surfaces. Something like a motorcycle chain is where an X ring excells. For a hydraulic oil seal, an O ring is correct for the job.

[cabezaverde]

Thanks for your help guys.

The seal was like a flat o ring, looked sorta like a hose washer. Not having a nearby source I replaced it with an o ring, and the leak is stopped!

[jsizemore]

The original may have been round when it started life. If they are the wrong material composition for the application they will shrink and harden to a new shape after being put through high pressure and the high heat that comes with it.

[megasupermagnum]

Yes, old O rings often take on an almost square shape with time.

[jsizemore]

Yes, old O rings often take on an almost square shape with time.

And may swell when the o-ring material absorbs the fluid it's controlling.