hoist pump quit working?

PJH · Oct 7, 2015

The hoist pump on my trailer quit pumping. I have a connector to operate the hoist from my tractor hydraulics, and it still works with power from the tractor, so that narrows the problem to the pump/valve assembly. It quit suddenly - I hauled four loads of gravel and it dumped them just fine, but refused to work on load five. Everything looks normal, except for some air bubbles escaping around the valve spool. Is this thing repairable, and are parts available? I haven't cleaned it up for name and number yet, but figured some of the old truck guys on here would recognize it and be familiar with it from past experience. Thanks for any tips.

RogerinIowa · Oct 7, 2015

Are you sure the valve spool is working properly? Is the valve moving too far or not far enough.

Odd for a pump to just quit! Is shaft of pump turning?

PJH · Oct 7, 2015

Roger - I thought it was odd the way it suddenly quit. Shaft is turning. In one of the pictures, you can see a ball valve that I close when I use the tractor hydraulics. The ball valve keeps pressure from the tractor from backflowing the trailer pump. Today, after it quit pumping, I slowly moved the ball valve partially closed, and it pulled the engine down and killed it. That tells me that the pump is making pressure, but why is it not raising the cylinders. I plug the tractor onto it, and it works like it always did. Tractor is a JD 630 with maybe 1200 PSI hydraulic pressure. I think I'm gonna have to add a pressure gauge to see what exactly is going on. It's a mystery, so far. Thanks for the response.

Steve@Advance · Oct 7, 2015

Being it's a gear pump, and it suddenly quit, my guess is a key sheared, either from gradual wear and finally sheared off, or something got in the pump and locked it up.

It's possible it could be repaired, just have to open it up, see what happened.

Paul Janke · Oct 8, 2015

A really common cause for a hydraulic pump to quit suddenly is when a suction line collapses on the inside. I have replaced pumps only to discover later that the problem was that the pump couldn't get anything to pump because of a bad hose.

PJH · Oct 8, 2015

Good idea! All of the lines are relatively new, except for the suction line.

PJH · Oct 8, 2015

Thanks Steve - it's an ancient pump, and has had lots of use. I hope it's fixable. It's in the repair line, as soon as I can get to it.

RogerinIowa · Oct 8, 2015

Don't overlook the suction line since the pump is making pressure but maybe not flow. Maybe the flow is too much when trying to work properly but has enough flow that the ball valve blocking off the flow causes the engine to die.

I think it is the suction line....

PJH · Oct 8, 2015

Thanks Roger - you guys have been a big help! Everything points to an obstructed suction line.

DGinVT · Oct 9, 2015

If it is the suction line make sure you use a reinforced piece of hose.

hoist pump quit working?

PJH

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RogerinIowa

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PJH

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Steve@Advance

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Paul Janke

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PJH

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RogerinIowa

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