John Deere 4040 hydraulic leak

Jmr236 · Jan 31, 2020

I am new to the forum and recently purchased a John Deere 4040. The tractor runs great but I recently noticed that when warmed up there is a small hydraulic leak coming from under the right side of the cab. The leak only seems to occur when the brakes are applied. Both brakes function normally. When looking under the cab all I can tell is that the leak appears to be coming possibly from the hoses that go up into the cab above the attenuator since all of the of the lines below them have oil on them. The leak appears to be small and I'm trying to see how big of a job is this to do? Is it best to let the dealer mess with it? How much would it be to have fixed ( ballpark)? Or this just part of owning a 40 year old tractor and not something to worry about? Any advice would be appreciated. Thanks

Janicholson · Jan 31, 2020

Two items. If the tractor is mission critical, fixing it now is correct. A small leak can, and probably will, get bigger, and may
burst. If not mission critical, fix it over time. Winter is a reasonable time.
And it is a part of living with modestly old tractors. Jim

Bob · Jan 31, 2020

Your tractor has a closed center hydraulic system and there's lots of hoses and lines in that area that are under a constant pressure of 2250 PSI or so.

You say the leak is worse when the brakes are applied, that would typically narrow down the problem to the brake valve or the left or right brake line.

Take a closer look, and figure out EXACTLY where the leak is actually coming from, just take precautions not to get your skin or eyeballs in the way of a high pressure oil leak.

Once you figure out EXACTLY what's leaking, post back.

Jmr236 · Jan 31, 2020

Thanks for the information. What is the best way to access the top ends of the hoses and lines? I can see them from underneath the tractor but can't really get to them.

Bob · Feb 1, 2020

(quoted from post at 00:33:03 02/01/20) Thanks for the information. What is the best way to access the top ends of the hoses and lines? I can see them from underneath the tractor but can't really get to them.

Remove the rubber floor mat, then unbolt the steel access plate beneath it and remove.

Take wrap-around covers off of sides of steering pedestal, if needed

4520BW · Feb 1, 2020

My guess would be the plastic line from
the pump. They get brittle and crack.

Jmr236 · Feb 1, 2020

Ok thanks. I will take a look at it

Jmr236 · Feb 23, 2020

I took the plate off and it appears that the outside brake hose that connects to the cab is leaking possibly at the coupler that connects to the hose in the cab. It is hard to see because due to the lack of room to maneuver in the cab. The hose in the cab is dry but the coupler underneath the cab right under the floor plate has hydraulic fluid on it. Is there a better way to access this hose or does it involve removing the cab or other pieces to get to it?

John Deere 4040 hydraulic leak

Jmr236

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Janicholson

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Bob

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Jmr236

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Bob

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4520BW

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Jmr236

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Jmr236

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