40 S John Deere

Nat

Member
Mman helped me with my last problem so now I'm on to the next one. I assume the hydraulic pump is leaking into the crankcase cause it keeps getting overfull of oil. When I got it home the oil was way over full. I wasn't sure if it was really that full or if it had the wrong dipstick. I drained the old oil and Got nearly 4 gallons out of it. After putting in the correct amount in I can tell that it is the correct dipstick. After running it a good bit trying to get the RPMs right and adjusting the governor I checked the oil and it is over full and the hydraulic system is now low. After looking at the hydraulic pump breakdown it doesn't list a seal assembly which I assumed was the problem. So how am I getting Hy-fluid in my crankcase? Is there a seal that I don't see on the parts drawing?
 

Seal is an o-ring(parts key 8) Part number is M1866T which subs to U11647 . Spec's of o-ring pictured below

36006.jpg
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Thanks, that is the same breakdown that I have. Is it a generic o-ring or something you have to get from JD?
 
(quoted from post at 13:45:57 05/16/16) Thanks, that is the same breakdown that I have. Is it a generic o-ring or something you have to get from JD?

Part number from JD dealer is U11647
Specification's to get o-ring a supplier other than JD are in PHOTO BELOW.

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H4D is a John Deere spec...

"JDM H4D CH 90 durometer nitrile, peroxide cured"

I don't know whether all nitrile o-rings are "peroxide cured" or it that is a special process for JD.

If you find a non-JD source for this part, you will likely have to buy 100 to get 2. I'm very big on finding generic sources for overpriced OE parts, but in this case I would bite the bullet and order the JD part.
 
I tried to zoom in on that and if I got it big enough to see it was too blurry to read Thanks. It's not that far to the JD dealer so I guess I'll go there
 
(quoted from post at 14:42:50 05/16/16) I tried to zoom in on that and if I got it big enough to see it was too blurry to read Thanks. It's not that far to the JD dealer so I guess I'll go there

my two cents... if you're going to pull it off and pull it apart, it might make sense to replace the bearings as well. they are potentially a least as old as the o-ring and don't cost much.
 
If it were me in addition I would order the bearings - key 9 & 16 as well as the gasket set key 21 as well as the seal that go's in the large suction line.(M1040T)
 
Mman, it's clear you know what you're talking about so I'll call JD and get them coming, doubt they are in stock. Is it much job to Change?
 
Did this on my MT a few years back for the same reason. You have to remove the hood and grill and I also removed the radiator to get at the hex head cap screws. You may strip one or two of those getting them out if they are really in there. I luckily only stripped out one. Beyond that it was not difficult to get the pump itself apart. Make sure you have a clean place, really clean, to rebuild the pump itself. I also recommend you look at the radiator mounts while in there. They are rubber with a metal spacer in them and could be shot. The ones on my MT were pretty shot so I replaced those and the radiator hoses as well as the fan and alternator belt while I was in there. Hate to take something that far apart and have to do it again any time soon. I was able to source everything from JD however also check out Sharp's Antique tractors. I was able to get some of the parts cheaper through them than Deere and the quality and service from Sharp's has been good in my experience on multiple orders over the years.
 
Keep me (us) posted on your problems/progress. I'm following right along behind you with my 40S, and have never had the pump open.
 
I'll try. I called JD dealer this morning and ordered the parts. I hope your's hasn't been treated like this one has. I have it running pretty good and it works great. I have a 6 foot 20 Disc harrow that is almost to heavy to pick up and it will just walk with it at a fast idle in third gear. Much stoughter tractor than it should be but every thing has been let go on it, I mean no maintance
 
I have to take the radiater off anyway cause it doesn't have a generator on it. They just charged the battery whenever it died so to put a belt on It is easier to remove the radiator. It would be nice to have just one thing go right on this rehab, o far nothing else has
 

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