John Deere 350 hydraulic system pressure relief valve o-rings sought

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Lavoy
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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by Lavoy » Sun Oct 19, 2025 7:33 pm

I have had pretty fair luck with Seafoam to get moisture out of hyd oil. Heat is also good, but you need the hyd oil hit for half an hour or so.
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briancady413
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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by briancady413 » Mon Oct 20, 2025 4:17 pm

Lavoy, thanks for the tip - what's Seafoam? It turns out that this hydraulic oil had foamed, as it became clear after sitting some days.

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Stan Disbrow
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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by Stan Disbrow » Tue Oct 21, 2025 8:20 am

Hi,

https://shop.advanceautoparts.com/p/sea ... gKTSfD_BwE

In other auto parts stores as well.

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by briancady413 » Sun Oct 26, 2025 2:38 pm

Thank you, Stan,

I just heard about the hydraulic pump disconnect lever - tomorrow I will check that.

Perhaps I was wrong about the hydraulic oil having foamed - maybe the milkiness going away was because water settled out at rest that had been mixed in while running.

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by briancady413 » Mon Oct 27, 2025 3:14 pm

Jim B. I apologize - you mentioned the hydraulic pump disconnect earlier. It turns out that the hydraulic pump disconnect lever is missing. There's a shaft and ball detente there, but no lever. I have asked the seller I bought it from if he has the lever. If not, I'll have to buy one.

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by Jim B » Mon Oct 27, 2025 3:25 pm

So, are you saying the pump drive has disconnected?

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by briancady413 » Mon Oct 27, 2025 3:52 pm

I am not sure - I saw the yoke and splines, but didn't start it today to see.

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by Jim B » Mon Oct 27, 2025 3:58 pm

Keep us posted

briancady413
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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by briancady413 » Mon Oct 27, 2025 5:24 pm

Well, the seller doesn't have it - He said they froze up often, so the handles were taken off frequently. I'd like to get that hydraulic pump disconnecct lever (part # T21136) and the groove pin (25H50). I'd also like to get a track roller that has the grease fitting for the special slide-on tip of the grease gun. I have seven mounted, as well as three non-lube-able track rollers on there, and I have two spare lube-able track rollers to put on sometime. Also, I'd like to get a working auxiliary hydraulic control valve, that bolts to the loader boom and bucket control valves - The one there is frozen.

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by LeonardL » Tue Oct 28, 2025 8:56 am

Your best bet for your parts is a salvage yard. Out your direction there is ( PB&H Equipment Parts - 1-888-588-3005 ) Or here in Missouri there is ( Zimmerman Tractor - 1-573-378-7210 ) The guys at PB&H are great to help with information as well.
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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by Jim B » Tue Oct 28, 2025 9:48 am

I have gotten a couple things from PB&H. They are good guys. Thanks for the reminder, Leonard.

The handle missing won't stop your pump from working unless the disconnect has opened. If you can reach in there and turn the pump shaft by hand or with pliers it has opened and likely why your hydraulics quit all at once. If it won't turn/tries to turn the engine the drive is engaged and should be turning the pump.

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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by briancady413 » Tue Nov 04, 2025 4:08 pm

Bacon's Equipment of Williamsburg will install the hydraulic disconnect lever, fix the hydraulic system, install the auxiliary valve and put on the timber rollcage. Bacon's Equipment was recommended by Freeland, who moved away, and who himself was recommended by two others.

Brian
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Re: John Deere 350 hydraulic system pressure relief valve o-rings sought

Post by Lavoy » Tue Nov 04, 2025 6:56 pm

Unless you really need the disconnect for very cold weather, I wouldn't waste the money, it serves no other purpose.
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