# Hydraulic pump dumping into crankcase



## belacdrofnats (2 mo ago)

I’m having problems with my hydraulic pump blowing a seal and dumping into my crankcase. I’m thinking there is a restriction somewhere but not sure how to find it. Also can I use the oil/hydraulic fluid I drained out of my crankcase in my hydraulic fluid until I can get the problem resolved? I hate to keep having to spend the money on new fluid only to have it dumped into my crankcase again. Thanks for any and all help.


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## bmaverick (Feb 20, 2014)

belacdrofnats said:


> I’m having problems with my hydraulic pump blowing a seal and dumping into my crankcase. I’m thinking there is a restriction somewhere but not sure how to find it. Also can I use the oil/hydraulic fluid I drained out of my crankcase in my hydraulic fluid until I can get the problem resolved? I hate to keep having to spend the money on new fluid only to have it dumped into my crankcase again. Thanks for any and all help.


I assume you have a Yanmar. Is this a sailboat, a crawler, a wheel-loader, a dozer or a tractor? And what model?


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## Groo (Jan 17, 2020)

need a new pump.
When a hydraulic pump fails, they often dump through the shaft seal. just changing the seal is not rebuilding the entire pump.
If you have a restriction between the pump and the main relief (usually on the valve), you will take out your pump. They are often the weak point.

motor oil is generally "better" than hydraulic oil. I have seen engine oil specced in very expensive machines for use in more extreme conditions.


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## belacdrofnats (2 mo ago)

bmaverick said:


> I assume you have a Yanmar. Is this a sailboat, a crawler, a wheel-loader, a dozer or a tractor? And what model?


Sorry I left that out. It’s a Yanmar YM 1601D tractor.


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## winston (Aug 19, 2008)

Is your lockout valve (right under the seat between your legs) wide open? Have a loader? If so, how plumbed?


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## Donnyg (2 mo ago)

I had the exact same issue with a Bolens. PO said he pu a bigger hydralic pump on it and then thought his battery was going dead on him. Turns out it was hydrolocked with oil. The seal on the pump was popped out. Put another used pump on and no more problem. I did change out the engine oil and replenish the hydo fluid. I know it's expensive stuff . I don't know enough about oil so the contaminated oil may be OK. I wouldn't take the chance myself.


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## belacdrofnats (2 mo ago)

winston said:


> Is your lockout valve (right under the seat between your legs) wide open? Have a loader? If so, how plumbed?


The valve is now all the way open. It does have a loader. I had the loader off and a bypass hose hooked up to the hydraulics and it ran fine, just wouldn’t raise my 3 point, so I put the loader back on and that’s when it blew the seal. I’m sorry but I’m new to tractors so I’m not sure how it’s plumbed. Would it be possible that the hydraulic hose on the loader be clogged or have a restriction?


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## Fedup (Feb 25, 2014)

Possible? Yes but far more likely it's just hooked up wrong. Amazing how often that happens.


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## Donnyg (2 mo ago)

I am no expert but I think your pump is dead or dying. If it's blowing the seal for any reason it's malfunctioning. from my trial and error experience i've hooked up things wrong so the pump was dead headed and made the pump scream but did'n't pop the seal. In a well functioning pump there should be very little internal pressure on the seal. As for the 3 point hydraulics it may be as simple as lost prime. Whe i replaced the pump on my tractor I filled the trans case up with fluid and tried the controls with no response.I injected some slight air pressure into the little trans case vent while the pump was running. It forced the oil up the pump intake tube and the pump was primed and the 3 point started working. If you try this do not force a lot of air pressure into the trans case!!! Very slight is all that's needed.


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## winston (Aug 19, 2008)

Can you take pictures and give a description of lines starting at the pump, on through the loader, and then on to the 3 point?


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