# Log Splitter Filter Problem.. Help



## angelom (Sep 2, 2006)

Hello everyone,

I have a northern log splitter that I have had for 15 years. There has never been any problems with it, until this year. What seems to be happening is when the blade is splitting wood, the pressure causes the filter to spray oil out. I've tightened it as hard as I can and this problem still happens after 5 minutes or so of operation. Also I've already used 2 new filters, and I know it is not the filter. Could it be the detent valve? 

Please post back with help.

Thanks,
Angelo


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## CaseyForrest (Sep 2, 2006)

It could be your relief valve stuck and not opening when it should. It could also be a fine hairline crak in your filter housing. 

First thing is get a gauge in-between your pump and valve. See if you are going over 3000psi. If you arent, replace the filter housing. They are not expensive, I think $30 down at the local TSC, or Farm and Fleet.


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## angelom (Sep 2, 2006)

Thank you for responding so quickly. I replaced the filter housing when I bought the new filter; so I don't think it is that. I think you are right that it may be the relief valve. Is the relief valve located into the detent valve? Is it repairable? 

It seems like there is alot of pressure going through the filter because it expands everytime it is under pressure, and it contracts when it is not under pressure.


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## tawilson (Sep 3, 2006)

If it's a Prince valve, you can go here to get the instruction manual and anything else you want.http://www.princehyd.com/Default.aspx?tabid=46


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## woodchop (Sep 3, 2006)

Usually the filter is on the return side of the pump ,the return is sized to the pump capacityand the return lines are larger than the inlet lines. This is done to lower the return pressure.
If there is a restriction in the return, cracked or inner liner of the hydraulic hose collapsed, than the pressure will go up in the filter.
You also mentioned that you can see the filter expand, every time it's under pressure. Does this happen when you use the valve?
Like mentioned above start checking with guages.


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## Patrick62 (Sep 4, 2006)

*This doesn't make sense*

If the splitter was setup correctly, the filter is in the return line to the tank. It will have a built in bypass valve that allows oil to bypass the filter when too thick.

The pump feeds the valve, and then the cylinder.... The oil is then returned to the tank. There should not be any pressure there at all!!! You mentioned that it only does is when the cylinder is under pressure? I am going to have to go with the theory of a collapsed lining in the return hose. Cold the fluid might be flowing slower, when warmed up it flows a little faster and the obstruction then flops, blocking flow. Also when in return stroke there is actually about 10% more oil returning than when in foreward...

my $0.02 worth
-pat


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## tawilson (Sep 5, 2006)

I've been stewing on this one too. I'd go with the collapsed hose too, but wouldn't it build up pressure all the time, not just when splitting? Sounds like the filter is between the valve and the cylinder, even though I know it can't be.


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## mga (Sep 5, 2006)

i'm going along with everyone else on this one: a collapsed line. pressure to the tank is supposed to be low, and if your oil filter is expanding as you say, then apparently something is obstructing the oil. this liittle diagram shows the pressure:
http://science.howstuffworks.com/hydraulic2.htm

disconnect the line between the filter and the tank and inspect for damage. 

is there pressure in the tank as well? the filter might be reacting to pressure buildup from the tank. often there is a screen on the suction line that may get clogged.

added suggestion:
*you can try running it without the cap on the tank to see if the problem goes away. if it does, then, as many have said, check the vent.*


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## angelom (Sep 5, 2006)

Hello everyone, 

Thanks for the feedback, I called Northern customer service, explained the problem and they told me that I have air in the line and I must bleed out the air. In the next couple of days I will try to do this, and will keep you guys posted.

Thanks again,
Angelo


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## 1CallLandscape (Sep 5, 2006)

*northern/ air locked is BS*

I would have to agree with everybodu else of the collapsed line or The other thing to check is :

the inlet side of the filter---check for any debris clogging the inlet hole, if a piece of the lining collapsed and broke off it could be lodged in the inlet. 

*As MGA said also about tank pressure, check for a clogged tank vent. *
hope this helps


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## woodchop (Sep 5, 2006)

If you have air in the line than either the fluid is low or you have a plugged strainer. This would make the pump produce shattering noises too, but you did not mention that. Is the color of the oil leaking out of the filter milky or clear?


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## tawilson (Sep 5, 2006)

I think customer service steered you wrong. You shouldn't have to bleed anything. A few cycles of the cylinder should push the air to the tank. I ask again, wouldn't a collapsed line cause it to happen all the time, as the pump is pumping constantly, it's just not going through the cylinder unless the valve sends it there.


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## JeffHK454 (Sep 5, 2006)

I had a similar problem on a mobile press, which is basically a wood splitter. 


The vent cap had been damaged and looked to be in good condition but actually was not letting the tank stay unpressurized. The on/off pressure spikes on the low/no pressure side worked the filter threads until it blew the filter off like a missile! 

"Air in the system" is the standard answer for everything that goes wrong when it comes to hydraulics! 

I would say that it takes a couple hundred PSI to swell a filter housing so be careful it can still hurt ya! 

Jeff


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## jags (Sep 6, 2006)

Really there are only a few things that can cause this: the OUTBOUND side of the filter going to the tank is restricted, wrong type of filter, the hose from the filter to the tank is restricted, pressure is being created in the tank (from plugged breather), or you poured 90W oil in the hydraulic system (the last one was a joke.......I think  ) SOMETHING is stopping the "free flow" of the oil as it EXITS the filter assembly to the tank. Just MTC


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## ray benson (Sep 6, 2006)

Did the problem arise after the filter housing was replaced? The housing has an arrow on it to show the direction of the oil flow. If it is on backwards the filter could rupture. Also saw where the filter rubber gasket stuck to the housing. Then another filter was installed and we had double gaskets. The filter leaked no matter how much it was tightened.


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## angelom (Sep 6, 2006)

Hello guys,

The dilemma continues. Today I followed the instructions that northern told me to by letting the air out but it didn't fix anything. The same problem occured again. I drained the oil and I checked the hoses and there is nothing wrong with the them. The filter housing is in the correct position. I refilled the oil tank, turned the wood splitter on and the same situation occurs when the splitter is under pressure. The oil filter jerks around every time the piston is under pressure and when the piston is all the way out or when it retracts until it stops. I am thinking that something might be wrong inside the valve. It seems like it is letting high pressure escape through the return. I will call northern back and see what other solutions they may have.

Thanks,
Angelo


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## JeffHK454 (Sep 6, 2006)

Is the reservoir vented?
Is the system overfilled?

Your wasting your time bleeding the system of air, that's a standard " leave me alone , go away" from the so-called help line. 

If you had air in the system your pump would be cavitating like crazy , the cyl would be very "jerky" and the oil would be foamed. 

From the "return to tank" side of your directional valve to the end of the hose that lets out oil in your reservoir that oil should encounter very little resistance. Other than pushing oil through the filter element or over the filter bypass there's not much slowing it down, when there is you get things like swelled filters or split return lines. 

When you say under pressure do you mean running the cyl. in and out or actually splitting wood?

Is it possible to skip the filter and go from the "to tank" side of the directional valve straight to the tank, preferable with a new piece of hose? 

You only get pressure in a hyd. system if the moving oil runs into resistance, if your valve was leaking it would just never generate pressure , just a bunch of heat! 

What little I learned in hyd. class was this "hydraulic pumps create flow , resistance creates pressure" or something like that. 


Jeff


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## tawilson (Sep 7, 2006)

Thanks Jeff, that's what I was trying to get at, the flow is there whether you are using the valve or not, if it was a collapsed hose it should happen all the time. I thought the plugged vent was going to be the culprit, guess not.


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## turnkey4099 (Sep 7, 2006)

Afte all you have checked, I would bypass the filter and see what happens. There is very obviously a restriction somewhere, either in the filter or from the filter to the tank. My bet is that it will be in the filter. That is the only way pressure can build in your return line. Be sure that you do not have a restrictor fitting in the line. That happened to me and I had much the same symptoms you are having. The fitting I found was the swivel connector at the cylinder.

Harry K


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## angelom (Sep 7, 2006)

Hello everyone,

I narrowed down the problem with my splitter. I took off the filter housing and connected the hose directly into the valve. I manually held the end of the hose into the inlet of the splitter tank, turned the engine on, and the fluid flowed out nicely with no problems. Then I started to run the cylinder all the way out, as soon as the cylinder got to the end of the stroke, I noticed fluid stopped flowing and I noticed the hoses from the pump to the valve were twisting. I quickly released the handle and a burst of oil came out of the hose, and I almost lost my grip on the hose. I retracted the cylinder all the way, and the same thing happened. I put a knotted log in the splitter and as soon as the cylinder could not split the knotted log the hoses started spraying oil in short spurts. I noticed the pressure was building into the hose from the pump to the valve. So, this all tells me the problem is in the valve. I unscrewed the pressure relief valve and the spring/ball inside seemed to be fine. I re-installed it, and I tried relieving pressure and adding pressure, but the same problem occurred. So, I guess buying a new valve would be my best bet, instead of trying to fix it. 

Cheers,
Angelo


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## woodchop (Sep 10, 2006)

Buy a new hose that is long enough to go from the valve directly to the inlet of the tank and *install it*.Than operate the splitter.
Do not hold loose hydraulic hoses in your'e hand in an operating system. You can get killed doing that. Fluid under pressure will blow right through the skin and you will get a fine case of blood poisoning.
The short spurts were from the pressure relief valve releasing about 2500 PSI of pressure. The burst of oil came from the pressure build up in the system and releasing when the valve port went into neutral.( open).


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## mga (Sep 10, 2006)

woodchop said:


> Buy a new hose that is long enough to go from the valve directly to the inlet of the tank and *install it*.Than operate the splitter.
> Do not hold loose hydraulic hoses in your'e hand in an operating system. You can get killed doing that. Fluid under pressure will blow right through the skin and you will get a fine case of blood poisoning.
> The short spurts were from the pressure relief valve releasing about 2500 PSI of pressure. The burst of oil came from the pressure build up in the system and releasing when the valve port went into neutral.( open).




so....what you're saying is that the relief valve is malfunctioning?


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## woodchop (Sep 10, 2006)

Relief valve is functioning. It's releasing at the pressure it is set at and protecting the hydraulic system.


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## woodchop (Sep 10, 2006)

This might help:

http://www.northernhydraulics.net/ws/aboutus3.php?page_id=3655

Scroll to the bottom of the page. 

I know it mentions under leakage to check the relief valve, but this is for leaks on the pressure side of the system.
The return side of the system has some pressure, but not near as high as the pressure side. 
Like others have mentioned in the forum, a hydraulic system that has a pump coupled to an engine and that pump is rated for 20 GPM, it will pump 20 GPM as soon as the engine is running at operating speed, all the time. Not just when you operate the lever to move the cylinder.


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## mga (Sep 11, 2006)

woodchop said:


> This might help:
> 
> http://www.northernhydraulics.net/ws/aboutus3.php?page_id=3655
> 
> ...



great link....thanks!!!

i realize that one side of the system will have flow only and low pressure, but reading his post, he mentioned that while holding the hose it almost flew out of his hand. apparently, something is causing a burst of high pressure into the return line while under load. 

since he has checked the hoses for obstructions and the tank vent, then the only culprit can be the control valve. so, and i'm taking a wild guess at this one...the relief valve must be allowing the oil to blow by at a certain pressure all at once. ya think?


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## woodchop (Sep 11, 2006)

Re:something is causing a burst of high pressure into the return line while under load. 
The valve position is releasing the pressure from the cylinder and hoses or the relief valve it working.

Re:the relief valve must be allowing the oil to blow by at a certain pressure all at once.
Relieve valve releases at setting and closes when pressure is low.

In both cases the return side is designed to take this burst of oil unless there is a restriction. It's just more pronounced when you do not install the hoses and hold it in your'e hand. If you have a spitter deadhead the cylinder and with your'e hand on the return hose, move valve to neutral quick. You can feel the hose swell and jump in your'e hand.


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## mga (Sep 15, 2006)

ha...it must be a curse.

i let my brother-in-law borrrow the splitter for the past month. he mentioend that the filter was leaking oil...same situation...on the push stroke...and pull. he said he tried to tighten the filter the best he could...still leaked.

i brought it back home and started it up...he was right. so, i removed it completely and the seal remained in place. when i carefully removed the seal, i noticed a small speck of something there...in the same area the leak was (on the outside of the filter). i wiped the seal clean, wiped the inside boss where it sits clean, wiped the filter clean and hand tightened everything.

started it up....threw a log in...no leaks.


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## angelom (Sep 15, 2006)

Everyone,

I finally fixed the problem. I installed a new valve and it works perfectly now. I want thank all of you for your input. Time to go split wood! 

Thanks,
Angelo


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## mga (Sep 16, 2006)

angelom said:


> Everyone,
> 
> I finally fixed the problem. I installed a new valve and it works perfectly now. I want thank all of you for your input. Time to go split wood!
> 
> ...



whoa...wait a sec...just for future reference...what was it about the valve that made it do that? were the seals gone? was it the relief valve?


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## JeffHK454 (Sep 16, 2006)

I think that it's hard to try to both describe and diagnose hydraulic problems over the inter-web! I've seen directional valves malfunction and spike the lines and make them jump but never swell a filter, I would think that would take something between the out side of the valve and the tank impeding the oils flow. 

It works now , that's all that matters!


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## mga (Sep 17, 2006)

> It works now , that's all that matters!



true. but, i just thought for future reference it would be good to know if what was broke on the controller. so, the next time someone posts about a leaking oil filter a possible solution is archived in the forum.

by the way...how tight do you guys turn your filters?


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