Log Splitter Hydraulics NO FLOW

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Log Splitter Hydraulics NO FLOW

Postby kirkcudbright » Sat Aug 19, 2017 5:56 pm

The log splitter I use was somebody's AG class project probably twenty years ago. So I have no make and model information.

Today, I replaced the pump which had developed a substantial leak and couldn't be removed without breaking the shaft. Northern tool had an identical unit. It has no flow, and I just put a different one on that has the same problem.

Free flow of fresh fluid from the tank to the supply side of the pump.
No pressure between the pump output and the control valve.
No flow back into the reservoir.
No flow from pump output (checked by disconnected control valve and running output hose directly back to reservoir)
PTO engages, pump pulley turns, and pump shaft is turning (pulley isn't slipping).
No change in engine when PTO is cycled.
Pump input hose is not collapsing.
Pump input hose gurgling. Pushing pulses of air back out inlet (observed through transparent hose)
The engine is clockwise, and the pump is designed for clockwise operation.
The hydraulic fluid reservoir is filled to several inches above the outlet (that feeds the pump's inlet).
The old pump worked when hooked up in the same way as the new pump.

What I did to hook up the pump...
Disconnected old pump.
Replaced pump input hose.
Replaced pump output hose.
Replaced pressure gauge.
Replaced pump pulley
Installed new pump (which had same form factor as old pump).
Adjusted belt.
Turned a probably ten revolutions to prime pump (but noticed it already had oil in it).
Started it up.
Went through the process again with a second pump.

What *I think* I know...
The control valve, cylinder, hoses, and filter are irrelevant because I get no flow out of the pump when I disconnect all of them.
Bleeding the system shouldn't have been an issue because air elsewhere wouldn't stop the pump from pushing out fluid.
If I have an unrestricted flow going into the pump, and the pump is turning the right direction, then I should have *something* coming out of the output.

Clearly, there is something I think I know but don't.


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Re: Log Splitter Hydraulics NO FLOW

Postby ScottyD'sdad » Sat Aug 19, 2017 7:11 pm

Is it rotating in the right direction?
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Re: Log Splitter Hydraulics NO FLOW

Postby kirkcudbright » Sat Aug 19, 2017 7:18 pm

You know what? It isn't.

I always thought rotation direction was described from the perspective of the pump, looking out at the shaft.

If was the case, I would be good.

But, it turns out it this is described from the perspective of the person looking in at the shaft.

That makes it backwards.

It also means I'm going to have to restructure the whole thing.


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