Log splitter problems

[Scott Allison]

Good morning I have an log splitter that my grandfather built over 25 years ago and has worked perfectly until this summer. It all of a sudden stopped going into the two stage stronger pressure. The hydraulic cylinder was also starting to leak heavily. I had the cylinder rebuilt by a machine shop first and no difference. I then had a mechanic friend put gauges on the supply line after the pump and it was under 500 psi when under pressure. We assumed it was the pump. I installed a new 16gpm pump, still no difference. I replaced the filter as well on the return line and cleaned the screen on the reservoir, no difference. We tried adjusting the detent valve to increase pressure and same. The detent was getting sloppy and it is at least 13 years old so I just replaced that as well. Still the same problem and Lovejoy coupling seems to not be slipping either. Any suggestions, I don't know what's left?

 

[sundance]

The only thing that comes to mind would be a bad hose. Where was the gage installed after the detent valve? I suppose the new pump or detent valve could be bad but seems unlikely. Sure the coupling isn't spinning? That currently seems the most likely.

 

[Scott Allison]

First, thanks for replying. We put the gauge before the detent valve on the supply line. The cylinder runs back and forth smoothly and will split kindling wood but the moment you go against anything bigger it stops. The motor doesn't work harder at all. We also checked the coupling and the key way lines right up and you can't stop it. Is it possible something is wrong with rebuilt cylinder? Hoses seem fine from outside they don't compress under pressure.

 

[sundance]

If the gage is on the pump output and never goes above 500 psig then I doubt it's an issue with the cylinder. From here (and not claiming to be an expert) it sounds like 1. the pump (yes, I know it's new) not kicking down or 2. the detent valve (yes, i know it's new) bypassing fluid instead of sending it to the cylinder. Cylinder itself doesn't seem a likely culprit..........Thinking about it as I type, I guess the cylinder could be bypassing internally and not building pressure.

All told, without some known good parts to work with it seems mighty tough to troubleshoot. Any chance you have access to another splitter with similar enough parts to do some swapping?

 

[Scott Allison]

I don't unfortunately.

 

[sundance]

Maybe post your location and see if anyone local could help out. Most on here are willing to help out within reason.

 

[coutufr]

Is there any hydraulic oil filter that might be clogged somewhere? How is the pump « knowing » that it has to increase pressure? Maybe there is some kind of safety switch on it somewhere. Ask the company who sold you the pump

 

[Scott Allison]

Hydraulic filter is on the return line to tank and I replaced it the other day so nbn it's new.

 

[speeco]

Hydraulic filter is on the return line to tank and I replaced it the other day so nbn it's new.

I would say cyl. Is leaking internally. Bad seals on piston ? Did the repair shop change out all the seals ? I have resealed a lot of cyls. And some times have had seals get damaged when putting cyl. Back together. Bore of cyl. bad ? Scored up. Just remove hose run splitter to see if it is bypassing internally. U have to have a tight system to build pressure to make pump shift into second stage. Good luck !

 

[VirginiaIron]

I would say cyl. Is leaking internally. Bad seals on piston ? Did the repair shop change out all the seals ? I have resealed a lot of cyls. And some times have had seals get damaged when putting cyl. Back together. Bore of cyl. bad ? Scored up. Just remove hose run splitter to see if it is bypassing internally. U have to have a tight system to build pressure to make pump shift into second stage. Good luck !

Remove one of the hoses on the cylinder and dead-head the rod closest to the hose removed. There should not be any flow from the open port. Be sure to use some pads to prevent oil contamination of the environment and to protect yourself and anyone else in the area.

 

[VirginiaIron]

Depending on your type of valve, you may not have an adjustable detent and you are in fact adjusting pressure relief/bypass. If you have a valve with an adjustable detent, your bypass may be to low and require adjustment, not likely with two valves. You need to make sure you are adjusting the bypass and not the detent. Some two stage pumps have an adjustment for the first stage/two stage window that could be out of adjustment, but this is not likely withyour two pumps.

 

[moresnow]

Over 25 yrs old.. Any chance you have a hose collapsing internally? Just a thought. Kinda out there but?

 

[VirginiaIron]

Over 25 yrs old.. Any chance you have a hose collapsing internally? Just a thought. Kinda out there but?

I would think a high pressure should not matter and would eventually leak at that location. On a suction line the pump would cavitate and whine, and eventually fail.
Good point, In this case of a noisy whine, the OP might think it is normal operation.

Is the pump whining and making all tropes of noise and is the oil aerated?

 

[sundance]

I would say cyl. Is leaking internally. Bad seals on piston ? Did the repair shop change out all the seals ? I have resealed a lot of cyls. And some times have had seals get damaged when putting cyl. Back together. Bore of cyl. bad ? Scored up. Just remove hose run splitter to see if it is bypassing internally. U have to have a tight system to build pressure to make pump shift into second stage. Good luck !

After thought (see earlier post), I'm inclined to think this is the problem. Issue seems to have started with the cylinder so likely still the problem.

 

[speeco]

After thought (see earlier post), I'm inclined to think this is the problem. Issue seems to have started with the cylinder so likely still the problem.

i would agree with you.

 

[sb47]

I have seen several rebuilt cylinders have issues and needed to be done again. Just because it's freshly rebuilt doesn't mean it's still not the problem.

 

[Bobby Kirbos]

1. Drain the oil from the cylinder.
2. Adapt cylinder connections for air fittings - include a pressure gauge. Make sure the fittings are sealed well.
   
3. Pump up cylinder to 100psi with air.
4. If you have a leak in your cylinder:
   • you will hear air leaking inside as you pressurize the cylinder.
   • the pressure gauge will show you if you don't hear anything.

 

[Jhenderson]

1. Drain the oil from the cylinder.
2. Adapt cylinder connections for air fittings - include a pressure gauge. Make sure the fittings are sealed well.
   
3. Pump up cylinder to 100psi with air.
4. If you have a leak in your cylinder:
   • you will hear air leaking inside as you pressurize the cylinder.
   • the pressure gauge will show you if you don't hear anything.

Why on earth would you go through all that when you can dead head the cyl, pull the hose, and pull the lever. If the cyl is bypassing fluid will come out the open port. End of diagnosis.

 

[Cowdudy]

Why on earth would you go through all that when you can dead head the cyl, pull the hose, and pull the lever. If the cyl is bypassing fluid will come out the open port. End of diagnosis.

I 2nd that. Also let it run for a while and check for hot spots. If it’s a valve bypassing or adjustable pressure relief you will see the temp rise with run time. Check the pump for heat as well should be about 100 degrees over ambient temp after warm up.



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[kevin j]

-don’t use air for testing. Compressible fluid stores energy and when something moves it can move a LOT and a long ways.

-cyl seals could be damaged or tube bore corroded or damaged at certain places in stroke.. just putting in new seals may not solve mechanical issues.

-Remove both hoses from cylinder and cap/plug. cycle the valve and see if the pressure gauge reaches relief valve setting. Note, this does NOT verify a pump, as the pump can be almost shot but still hold pressure against deadhead. If relief valve can control the pressure properly, set that.

-reconnect the closed end hose to cylinder. Keep rod end hose plugged, and rod end of cylinder open to a drain. Stall the cylinder against a load, (some wood, crosswise?) through various parts of the stroke, not just at full extension. If you see a lot of oil coming out of the cylinder rod end, the piston seals are leaking, or the tube is damaged at thaty point in the stroke.. Or other issues inside cylinder and piston. .