looking for hydraulic problem solvers

[Patrick62]

Okay. Here is the machine in question.
This year it started overheating the hydraulic oil. I am trying to figure a logical method of determining why. We have been splitting with this for 5 something years out here, and it has seen well over 1000 cords of wood across that beam.
My first clue was it didn't seem as "zippy" as old blue usually is, and the second was it sounded "funny". Sounded like the engine was pulling a load when it really should not be. maybe I was imagining things...
Until I realized that my hook parked on top of that cylinder was noticeably hot to my hand, thru a string glove....
Seemed a little strange, and then when it ran out of fuel and I looked at the pile of splits, and said something ain't right. I got a cord out of one tank, when it really should have produced 50% more... seemed strange...

Then I touched the hydraulic tank and said "holy smoke". Way, way, hotter than it should be running. Something is definitely not right. I need to get this sorted out, wood season is coming.

Engine is a 15hp Kohler command pulling a 22gpm pump. large intake hose from 20 gallon tank on other side of beam. 3/4 hose to valve, and 3/4 hoses to 5" cylinder. 3/4 hoses on return line which feeds thru a valve that runs the drive motor (self propelled splitter). Hydraulic filter is in return line to tank.

I just changed the filter thinking that would be it, inconclusive. The only thing I can think of is a restriction somewhere.
The pump seems to be doing what it is supposed to do, it is pumping, and loading the engine. Splitting valve is working well, and the drive system seems to be okay.

I noticed that when retracting the cylinder the engine was loading up more than usual, and that might indicate that it isn't happy with the extra fluid displaced on retract. Which might indicate that the problem lies between the splitting valve and the tank?

I am thinking the first thing to try would be running a return line directly from split valve to tank, and see if that works. if so, then take apart the other stuff until I find something that ain't flowing well....

Ideas? Suggestions??

 

[triptester]

The return filter looks a little small for a 22 gpm pump. What could have happened is the bypass plunger in the filter base could have come apart partially blocking return flow.

 

[timbrjackrussel]

You need a pressure gauge in the system. When everything is at a no load setting, what is the pressure?

 

[chads]

I may be off here as hydraulics are not my strong suit but the bypass may not be working properly and causing it to run load at all times instead of recirulating.
Chad

 

[Patrick62]

Many thanks!
I am going to really look over that filter, and see that is the problem.
If so... then I will replace it with a larger one. I thought it was a 20 or a 25 gpm when I put it on years ago. Changed the cartridge a few times.

 

[Blowncrewcab]

The oil will get hot if the pump never gets unloaded. It seems like when your splitter head is all the way back (home position) that the valve isnt going back to center, causing the pump to be loaded when it should be in neutral (un loaded) if the filter hasnt gagged it in the last 5 yrs and it's new or Not clogged thats probably not it. Somethingelse is going on ... I have seen Hyd hoses breakdown on the inside causing flow problems which lead to heat problems...

 

[Patrick62]

ordered a 50gpm from Northern tool.
Going to test it by removing the filter and run it direct and see if all is back to normal (I bet it will be).

I used to have a pressure gauge on this one, got beaned by a block and removed.

 

[blades]

more than as was mentioned - valve problem - relief /bypass function stuck or the spring has broken.

 

[Patrick62]

hmmmm... if the releif valve was open I would not get pressure/flow to operate the cylinder?

I went out and unscrewed the filter, and looked in at the bypass valve and spring. All is as it is supposed to be there. Okay, this rig worked well for many hours... Blowncrewcab, I think you might be onto something with a de laminated hose.... and with it loading heavier on retract with higher gpm on retract... that leaves the return hose from the split valve to the drive valve as suspect.

I know, this isn't the way to "hook" it up, but dog gone it, it worked for years! I did not know there was such a thing as a power beyond valve when I built this machine. I hooked a second direction valve into the return line to operate the hydraulic motor to move the thing. when splitting the oil just flows thru that second valve. When driving the machine we are building pressure up against the return port of the first valve... wrong, I know. but it works. Could split the casting of the first valve in half!

I was out running it for half hour, and most of the time it appears to be running normally. Then something changes... for a little while... and it sounds funny.
The splitting valve is returning to neutral correctly. A loose and sloppy valve I would notice.

There was one time a year ago that Kurt was splitting and somehow he had managed to get the drive valve partway into drive... Just enough to back up pressure to get the pump down to low flow mode.... you know, 6gpm instead of 22gpm. Why in the heck the thing didn't just crawl away I don't know! He says the splitter isn't working right. I look over and the thing is really splitting very slowly... wtf? I look at the drive valve, and put it back to neutral, and all is good again.

I gotta check that hose sometime today. and while I am at it I will check the first hose as well.

 

[olympyk_999]

hmmmm... if the releif valve was open I would not get pressure/flow to operate the cylinder?

I went out and unscrewed the filter, and looked in at the bypass valve and spring. All is as it is supposed to be there. Okay, this rig worked well for many hours... Blowncrewcab, I think you might be onto something with a de laminated hose.... and with it loading heavier on retract with higher gpm on retract... that leaves the return hose from the split valve to the drive valve as suspect.

I know, this isn't the way to "hook" it up, but dog gone it, it worked for years! I did not know there was such a thing as a power beyond valve when I built this machine. I hooked a second direction valve into the return line to operate the hydraulic motor to move the thing. when splitting the oil just flows thru that second valve. When driving the machine we are building pressure up against the return port of the first valve... wrong, I know. but it works. Could split the casting of the first valve in half!

I was out running it for half hour, and most of the time it appears to be running normally. Then something changes... for a little while... and it sounds funny.
The splitting valve is returning to neutral correctly. A loose and sloppy valve I would notice.

There was one time a year ago that Kurt was splitting and somehow he had managed to get the drive valve partway into drive... Just enough to back up pressure to get the pump down to low flow mode.... you know, 6gpm instead of 22gpm. Why in the heck the thing didn't just crawl away I don't know! He says the splitter isn't working right. I look over and the thing is really splitting very slowly... wtf? I look at the drive valve, and put it back to neutral, and all is good again.

I gotta check that hose sometime today. and while I am at it I will check the first hose as well.

you mentioned it was slower... have you also noticed a decrease in splitting force?
im thinking possible piston seals are going, or your suction line is collapsing...is the suction hose actual suction rated hose (internal wire support) or just rubber hose?

 

[Patrick62]

speed of cycle seems to be the same, or very close to it. Force is no different. it is just working hard(er) pushing fluid thru a restriction somewhere.
Suction line is mostly correct. Wire hose to the last 3 inches from the pump, and then a hunk of radiator hose from there to the pump. I know, it ain't the correct way, but it has worked for the last 3 years (and 900 cords) that way. The pickup assembly in the tank is a piece of tubing with a thousand 1/16 inch holes drilled in it.

 

[blades]

pressure relief could stuck part way , worn barrel or oRings in valve also not discounting cylinder seals or collapsing hose or if you have a filter/stainer on the supply port to the pump that is blocked or disintegrating. lots of variables. Making up a gauge that can be swapped around in different areas would help define the problem location quickly. and of course water in the oil from condensation. Breather cap/port that is plugged. Cavation at the pump will cause a heck of a lot of heat

 

[kevin j]

Do you have access to temperature gun?
The place of restriction will have a very small but meaurable temp increase across it.
Pressure drop created by resistance turns to heat.
Pressure drop that does work does not turn to heat.

 

[sb47]

Pull the filter and start the splitter up and put the hand valve in neutral. If its circulating properly the oil should flow freely out of the filter fitting.
Use a clean bucket to catch and reuse the oil.
It shouldn't spew out but flow gently.

 

[GVS]

you mentioned it was slower... have you also noticed a decrease in splitting force?
im thinking possible piston seals are going, or your suction line is collapsing...is the suction hose actual suction rated hose (internal wire support) or just rubber hose?

Yes to the above especially a seal bypassing oil.That will really HEAT up some oil!