Need help with my log splitter

[vpd66]

Ok, I've had this Murry Mac log splitter for about 8 years and has never gave me any trouble. This year when I got it out to do some splitting, it has no power when it get into a piece of wood. I can run the cylinder all the way to the wedge without a piece of wood and run it back in, but has soon has it gets a load on it it has no power. Also when I return the cylinder from fully extended it spits oil out of the breather. the only thing I have done to it is change the filter and fluid , but it works the same. I have a strong mechanical background, but have only done oil leak repairs on hydraulic componants. So I need some advice on how to trouble shoot whats wrong with this log splitter. I don't want to just start throwing parts at this thing I want to do some tests and see something wrong.
Thanks

 

[Furu]

From your write-up it appears that it is a standalone with its own power supply, pump and reservoir and not running off your tractor's hydraulics.

If you have a hydraulic gauge that you can put on the system I would check to see if you have proper pressure for your system. The pump should have a plate with what the output PSI is spec'ed at. If the pressure is low that could cause the loss of power but should not cause the breather to spit.

With your comment on the breather spitting oil I presume that is the reservoir breather. My concern there is that the problem may be from fluid leaking past the cylinder sleeves and thus the loss of power and full pressure bleeding to the low pressure return line to the reservoir. Your valve could also have a similar issue leaking fluid to the low pressure return line creating all of the symptoms.

With out seeing the type of valve you have with your hydraulic plumbing that would be my first guess. JJ may see this and have a good idea as well as Kenny. Both are far superior to me on hydraulics trouble shooting.

 

[ilander]

Whenever I encounter a problem after maintenance that was not there just before maintenance, I usually find the person performing the maintenance accidentally created the problem. We all make mistakes.

Some hydraulic systems will not show maximum operating pressure unless a load is applied that opens the relief valve, if yours is the case, there could be nothing wrong with the pump internally if oil is bypassing somewhere in the circuit. Bypassing could be at the control valve, the relief valve or past the packings in the cylinder.

I assume the filter you changed is on the suction side, now if it is loose or somehow causing air to enter the system, then the pump could be trying to compress this entrapped air, and this entrapped air creates bubbles and expansion in the oil which could account for the spitting out of the breather. While the pump is trying to compress these air bubbles, there would be little power at the cylinder. I see this as a long shot.

It is possible during the filter change a small particle could have entered the system and is lodged between the pressure relief valve ball or plunger and seat.

Another probability is the pump drive could be damaged or lose, in that when there is no load, the pump turrns OK, but when a load is applied, the drive slips.

If you do not have a gage, bottom out the cylinder and listen to the engine. If there is no noticeable change in exhaust or engine noise, such as when a governor opens up, then there is no pressure being built up. I run my log splitter off a 1958 JD440 2 cylinder, when I split hard wood, that old engine really barks.

I wish you the best. Hopefully it is a simple economical fix.

 

[Willl]

I assume the filter you changed is on the suction side, now if it is loose or somehow causing air to enter the system, then the pump could be trying to compress this entrapped air, and this entrapped air creates bubbles and expansion in the oil which could account for the spitting out of the breather. While the pump is trying to compress these air bubbles, there would be little power at the cylinder. I see this as a long shot.

Maybe a long shot, but it's the only one that makes sense to the "spits oil out of the breather" .

 

[J_J]

Power is developed by the resistance to pressure.

I believe your tank is too full, or the excess fluid could be caused by air saturation. Air plus normal fill level = overflow.

If you install a gage in the IN port of the log splitter valve, you should be able to diagnose the problem.

If you run the cyl to the log and keep going, the pressure may build up, and if the wood is hard, pressure will build up quickly,

If you keep extending the cyl to the stop, then you should see max relief pressure.

If not, the pump is not putting out as expected.

Suction leak before or at pump inlet.

The relief valve might be held open by debris.

The cyl seals may be bypassing fluid.

How does the return cycle operate. Does the lever kick back to neutral.

Your filter normally should be on the return side.