1500D

[DAIRYMAN]

In a jam. I have a YM-1500D witha front end loader. It has been great for the last 5 years I've had it. About 2 weeks ago, I noticed transmission oil in the crankcase. I replaced the seal on the pump, thinking this was the only place for fluid to come from. Worked for another couple hours, and had fluid in the crankcase again. I broke down and bought a new pump, and after about 3 hrs of use, again, I had fluid in the crancase. Anyone have any thoughts or ideas? I don't think it's a pump problem, but what else could it be? Maybe backpressure?

Thanks

 

[kenmac]

How would you know the difference in transmission fluid in the engine crank from the engine oil. I'm sure that the transmission fluid ( in the engine crank case) would be black, just like the engine oil.

 

[DAIRYMAN]

I figured a good indication was the engine oil level going up and the transmission-hydraulic level going down. It wasn't just a trace of fluid, it was actually pushing out of the engine oil dipstick tube and the fill tube.

 

[Dick_Jermyn]

Is the crankcase vent plugged? Has a dirt dobber made a nest in the vent tube? Just a thought. Keep us informed.

Dick

 

[DAIRYMAN]

I'll check that out. I thought if that were the case, though, it would blow out of the shifter housing . There's nothing but a rubber boot on that. We'll see! Thanks for the reply.

 

[mark777]

DAIRYMAN,

I cannot put together any other way for hydraulic fluid to enter the crank case other than through the timing case cover via a bad pump seal. I know you've changed the seal, and also installed a new pump.

Is it possible that there is a burr on the shaft or something that seems insignificant, but enough to repeatedly damage the seal? The slightest deformation, burr or mating surface with an irregular shape may be causing the seal to continually fail.

Mark

 

[DAIRYMAN]

I checked the shaft on both the old and new pumps, and there were no imperfections that I could see. The vent tube was free and clean. I ran wire through it several times, and also dripped fluid through it. So.............

I appreciate all of the replies. I am open to ANY suggestions at this point!

 

[rock2610D]

Not sure if this will help but my owners manual for a 2610D states to clean the crankcase vent with a substance like diesel fuel. If you take off the plate that has the metal tube on it, there is some sort of gadget on the engine side that needs flushed out and cleaned. Maybe yours is clogged???

I am somewhat supprised that oil can come out of your dipstick tube. Mine is o-ringed and sealed pretty tight. It would take ALOT of pressure to push oil out of mine. Not sure if yours is the same though!!

 

[SATOHBULL]

Are you sure it is hydraulic fluid in the crankcase? It is fairly common for an injection pump to leak diesel into the crankcase when the seal goes bad.

The 'smell test' should tell you which it is.

If it is hydraulic fluid, I'm at a loss also.

 

[DAIRYMAN]

100% HYDRAULIC

 

[DavesTractor]

In a jam. I have a YM-1500D witha front end loader. It has been great for the last 5 years I've had it. About 2 weeks ago, I noticed transmission oil in the crankcase. I replaced the seal on the pump, thinking this was the only place for fluid to come from. Worked for another couple hours, and had fluid in the crankcase again. I broke down and bought a new pump, and after about 3 hrs of use, again, I had fluid in the crancase. Anyone have any thoughts or ideas? I don't think it's a pump problem, but what else could it be? Maybe backpressure?

Thanks

Looks like you have though this through. One idea would be to test the relief pressure. What if it is 3500 psi, instead of a more reasonable 2000 psi? It might be just high enough to force oil out the seal, but not quite high enough to shear the keyway or bust the pump. Unlikely, but an idea. The other thought is that the new pump is actually bad around the seal. What are the odds?

 

[HoyeTractor]

DairyMan,
We have actually received a lot of calls about this exact type of thing in the last few weeks (around 5 or 6 different people). Mostly on YM1500s 2000s, etc. I was happy to see your post here & thought someone would have an answer for you/us. Since you did not get any " I know exactly what is wrong..." answers I'll tell you what we found so far.

We have had customers with no loaders that have both the original pump & the replacement pumps start leaking large amounts of oil into the crankcase. At first we thought it was just an isolated incident but the calls kept coming. We have tried Yanmar brand replacement pumps, Japanese made aftermarket pumps, & even one of the Chinese aftermarket pumps on different tractors and they all leaked. I do not think it is a problem with the pump.

I called one of the pump manufacturers and they said that the pump shaft seal will normally see around 3-5psi and the seal will hold that amount of pressure. The only thing he could think of that could cause that to leak is pressure in the suction line or too much back pressure in the high pressure line. I agree with you and don't see how you could get pressure in the suction line on a Yanmar with the rubber shifter boot. I know that can't hold 5psi. So, according to the manufacturer, that leaves too much pressure in the high pressure line as a cause .

I agree with Dave. I would recommend one of our hydraulic pressure test kits here-->

Hydraulic Pressure Tester: Yanmar Tractor Parts

to see what your pressure readings are. We rent them now for $10.

I guess it could be that some tractors are now getting replacement valves during the import process that have too much relief pressure?? Please keep us posted if you find a cause.

Aaron
(940)592-0181
Parts@HoyeTractor.com

 

[DAIRYMAN]

Thanks, Aaron

I've got a tester on the way from you guys. Can you tell me off hand what the relief pressure should be?