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Discussion Starter · #1 ·
I recently purchased a used splitter with a PTO driven Prince pump made by American log splitter. I am having hydraulic problems. My system seems to be filling with air. With the valve in the neutral position (cylinder not moving in or out) it is constantly blowing air out of the tank vent. When splitting a piece of wood, after contacting the wood it hesitates a bit as though it is building pressure, then the ram suddenly and violently extends out about 3 inches sending the woodflying out off the end of the wedge. I have new fluid and the tank is filled above the return port to minimize air bubbles. I have no leaks, but seems air is getting in somehow. If the ram is partially cycled a few times near the end of the stroke, then returned. The fluid will blow right out the tank vent. Can I be sucking air in a seal in the pump somehow without it leaking fluid? Hope someone can help, this is driving me nuts.
 

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Hello oo7,

If you have checked the pump suction line connections at the pump and reservoir tank, then it has to be a leaking shaft seal on the pump. A suction leak may leave only minor traces of an oil leak. Have you checked the full length of the suction line? Also, you can apply sealant externally on connections to stop air entry.
 

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It is definitely sucking air into the system.
Many rigs will have a threaded in screen on the suction,
it sounds as if you are getting quite a restriction of the fluid suction and pulling a lot of air in.
 

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Discussion Starter · #5 ·
Hello oo7,

If you have checked the pump suction line connections at the pump and reservoir tank, then it has to be a leaking shaft seal on the pump. A suction leak may leave only minor traces of an oil leak. Have you checked the full length of the suction line? Also, you can apply sealant externally on connections to stop air entry.
Thanks so much for the reply BigT. I do question one of the barbed fittings on the suction side. At some time, someone replacing the line has driven a screwdriver down the length of the barbs creating a groove the length of the barb. No fluid is leaking, but I suppose air could be getting in. I was considering drizzling a little oil around the fitting to see if it would suck it in. I think now I will just change the fitting.You mentioned a sealant that could be applied What would that be? Thanks again
 

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Discussion Starter · #6 ·
It is definitely sucking air into the system.
Many rigs will have a threaded in screen on the suction,
it sounds as if you are getting quite a restriction of the fluid suction and pulling a lot of air in.
Thanks for the response Lou, I will check to see if there is a filter. Never thought there might be one.
 

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Discussion Starter · #8 ·
Hello oo7,

If you have checked the pump suction line connections at the pump and reservoir tank, then it has to be a leaking shaft seal on the pump. A suction leak may leave only minor traces of an oil leak. Have you checked the full length of the suction line? Also, you can apply sealant externally on connections to stop air entry.
Thanks for the response Lou, I will check to see if there is a filter. Never thought there might be one.
 

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Discussion Starter · #9 ·
Thanks so much for the reply BigT. I do question one of the barbed fittings on the suction side. At some time, someone replacing the line has driven a screwdriver down the length of the barbs creating a groove the length of the barb. No fluid is leaking, but I suppose air could be getting in. I was considering drizzling a little oil around the fitting to see if it would suck it in. I think now I will just change the fitting.You mentioned a sealant that could be applied What would that be? Thanks again
New shaft seals installed. I did notice a small amount of oil, and seals were cracked and dry looking. Working great now, thanks for your interest and encouragement
 
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