Hydraulic fluid in crank case. 2013 Yanmar LX490

[Raised on a Deere]

Posted on this topic in Parts and Repairs section but thought I might pass along here also.

Apparently my hydraulic pump shaft seals are leaking.(power steering or Hydraulics, there are two pumps driven off the same gear on left front of engine)

This could be from a failed seal or from pump being worn to the point that fluid is building excess pressure on seal and blowing it out. I don't know yet which pump is failing.

I have ordered new shaft seals from Messicks, and will be tearing into the system today to see what I find, hopefully it is not a blown seal indicating worn pump but just a seal that wore out or damaged in some other way. New pumps are around $500 on Messicks.

My Yanmar dealer went out of business, but still had access to parts ordering for a while, but finally got cut off. I found Messicks but parts were about double in price. They have otherwise been good to deal with, and have a comprenensive parts lookup system once you figure out how to get to it. I am just glad parts are available.

My tractor has about 1300 hours, has been flawless except for a few breaking hitch parts, and I have kept fluids and filters changed ahead of schedules.

Any experiences to share or parts sources much appreciated.

 

[fried1765]

Posted on this topic in Parts and Repairs section but thought I might pass along here also.

Apparently my hydraulic pump shaft seals are leaking.(power steering or Hydraulics, there are two pumps driven off the same gear on left front of engine)

This could be from a failed seal or from pump being worn to the point that fluid is building excess pressure on seal and blowing it out. I don't know yet which pump is failing.

I have ordered new shaft seals from Messicks, and will be tearing into the system today to see what I find, hopefully it is not a blown seal indicating worn pump but just a seal that wore out or damaged in some other way. New pumps are around $500 on Messicks.

My Yanmar dealer went out of business, but still had access to parts ordering for a while, but finally got cut off. I found Messicks but parts were about double in price. They have otherwise been good to deal with, and have a comprenensive parts lookup system once you figure out how to get to it. I am just glad parts are available.

My tractor has about 1300 hours, has been flawless except for a few breaking hitch parts, and I have kept fluids and filters changed ahead of schedules.

Any experiences to share or parts sources much appreciated.

Messick's may actually be the best company I have EVER dealt with, in my nearly 80 years on this planet!

 

[Roadworthy]

I had the same problem with my Mitsubishi, only it was an older model and parts were scarce. I got a brand new hydraulic pump from an eBay dealer for about $250. I suspect the dealer later found out what it was worth and raised the price to $400. Happy shopping.

 

[Raised on a Deere]

I got the pumps off and the seals appear to be pristine. Exactly like the new ones. So no obvious failure of the seals. I now suspect something internal in the pump that is allowing over pressurization of the seal so I am getting ready to take the pump apart and examine as closely as I know how. But there is an incredible thought in the back of my mind. Could hydraulic fluid enter by means of the crankshaft seal at rear of engine where it joins up with the clutch. This Yanmar has a wet clutch and is operated hydraulically. I know transmission case is not under pressure but I haver never seen these or similar tractors taken apart at the bellhousing. Is hydraulic oil separated from the crank case by a seal. I am looking up some diagrams to study this out. I hope someone who knows can tell me that no way for hydraulic fluid to enter engine by way of the rear crankshaft seal.

 

[Raised on a Deere]

Update: Found some wear in the Power Steering pump. Hydraulic pump passed my visual inspection but the power steering pump gear shaft bearing sleeves had allowed the drive gear in the pump to start rubbing the pump bore. At this time only very slight scuffing but never the less this may have been the cause of internal leakage that over pressurized the shaft seal that holds back fluid from the crank case. The seal itself look pristine and not actually blown in anyway that left any visible signs, but perhaps with the shaft being worn off center a bit it defeats the seal. Don't know yet. I installed a new seal and put the tractor back in service. Will watch the crankcase like a hawk for a few days, actually I will be checking oil level every day from now on. If I still have a leak i will know to just go ahead and order a new power steering pump.

Tractor has 1300 hours, I mistakenly changed fluid every 500 hours, but looking through my manual I see the interval is 300 hours. Don't know how I missed that.