JD 440 gas hydraulic troubles- oil going into engine.

dondeere · Post by **dondeere** » Fri May 18, 2012 8:23 am

I always try to give people the benefit of the doubt, however this time, I am confident all the problems were known and patched with a wing and a prayer...and a grin.
No worries, I paid alot for the crawler and am way over budget, but I will fix it properly and learn something in return.

Post by **Lavoy** » Fri May 18, 2012 9:26 am

Crawlers are an education, that is for sure. That is at least a partial reason I started a message board many years ago. To try and save some people the hard lessons I learned over the years.
Lavoy

dondeere · Post by **dondeere** » Fri May 18, 2012 10:08 am

I pulled the pump apart today and see that there is a seal on the shaft that has failed, however it does not show it on the parts list and photo for the pump?, it shows a washer, would this be the part?, I am going to JD today to see if I can order all the parts but fear they are obsolete.

DukeofDeere · Post by **DukeofDeere** » Fri May 18, 2012 8:38 pm

The O ring in front of the washer is what you may need.
Part 10 is part # m1866t

Duke

dondeere · Post by **dondeere** » Wed May 30, 2012 5:45 pm

the hydraulic pump has been repaired, the pump in the JD diagrams and parts page for the 420 and 440 is the same, but the parts are not, there is no "O" rings in pump or on the shaft, there is an oil seal on the outside of the housing and 2 square gaskets sealing the sections. They were very hard to find but I cross referenced the number on the seal and got one. I got it all put back together and dumped the old oil out of the engine, about 9 litres came out. Using the dip stick as a guide I put back about 5 litres. Obviously the extra 4 litres was hydraulic oil. Am going to fire it up tomorrow and see what happens. Hopefully it will run better, burn less oil and the hydraulics will be leak free. :)

dondeere · Post by **dondeere** » Fri Aug 24, 2012 5:47 pm

used the crawler a few times and noted the oil level increasing again and the hydraulic oil decreasing, I suspect that the pump is throwing hydraulic oil into the engine again for some unknown reason. I have an original owners manual and it says to use SAE 20 oil in the engine and SAE10 oil in the hydraulics in the summer and SAE 20 oil in the winter. I am currently using 10W30 engine oil and hygard oil in the hydraulics, I am concerned that having the hydraulic oil mixing with the engine oil will wreck the engine. I was wondering if I use SAE 20 in both the engine and hydraulics?, that way if it goes into the engine it won't wreck it. I have heard that SAE 20 is close to 10W30?
Any thoughts?

Post by **Lavoy** » Sat Aug 25, 2012 9:17 am

If you have a shaft seal, then that is the pump off of an M series, not a 440.
Yes, you can run engine oil in the hyd, won't hurt a thing.
Lavoy

dondeere · Post by **dondeere** » Sat Aug 25, 2012 9:53 am

ok, well it will not fix the oil from being sucked from the pump at least for now I will not have to worry about the hydraulic oil seizing the engine. I will have to monitor the engine oil level and drain some now and again and top up the hydraulic tank................at least it will be self changing until I take the pump out again. Any ideas as to why the pump seal keeps going, it only has about 3 hours on it?

Post by **Lavoy** » Sat Aug 25, 2012 4:56 pm

I have known a few people to fight them repeatedly. One problem might be system pressure. That pump is rated at 900PSI or so, 440 is likely set about 1050PSI unless someone has turned it up more. At that pressure, not sure it will ever hold oil.
Lavoy

dondeere · Post by **dondeere** » Sun Aug 26, 2012 9:18 pm

how do I turn down the pressure?

Post by **Lavoy** » Mon Aug 27, 2012 4:53 pm

If it is an original valve, there is a bypass setting on the pump, under a little acorn looking nut.
Lavoy

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JD 440 gas hydraulic troubles- oil going into engine.

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