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Discussion Starter #1
I'm trying to help a neighbor with his JD F725 mower that's blowing hydro fluid out of a hose. It looks like the hose is one of the metal tubes going into the junction box (?) at the base of the steering column. I'm thinking I don't want to get into this unless I have a tech manual or someone I can get some education from before digging a hole I can't get myself out of. I did a "search" here for the F725 and came up pretty much zero. Can anyone direct me to a website where I can get free access to a tech manual for this machine? Anyone who has extensive knowledge on this model could be a big help to.

Thanks in advance for your response.
 

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It’s not as intimidating as it seems.

I don’t know this model well I know what it is but I’ve never worked on one of those and if I am wrong you will know right away.

The junction box is really the base of the steering wheel and is the steering valve. It will have 4 or 5 ports. If it is 4 then it gets its oil supply from a hydraulic valve that control a deck raise/lower cylinder and priority is given to the cylinder over the steering. If it is a 5 port it supplies the hydraulic valve through the Aux port and priority is given to steering. Either way for what your doing it makes little difference.

Do not mix up the lines. On both types, 1 is for oil supply, 1 is for oil return, 1 goes to one side of the steering cylinder, 1 goes to the other side of the steering cylinder. If 5 port the fifth supply’s the auxiliaries.

You can either buy a replacement steel line but you have to see where it goes and is probably very hard to replace. You can replace the steel line with a 1/4” hydraulic hose. Some other models have steel lines, some have hoses from the factory. You might have to change the fittings. I believe the fittings are JIS to SAE o-ring 6 size but double check the size of the threads. The last one I did had hoses but for some reason I think you can use the JIS hose end on the same nipple that the flared metal tube is one. Even better below is some of the fittings and hoses I used on the last project on one of these.

Here is a good source for the fittings and hose. They also have a size chart that makes fitting sizes and thread size easy.
https://www.surpluscenter.com/Hydraulics/Hydraulic-Adapters-Fittings/JIC-to-SAE-O-ring/

It really is not more complicated than changing it out then firing it up and turning the wheel lock to locks few times to bleed it and recheck the oil level.
 

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Discussion Starter #3
Thanks for the come back. The hydraulic "tubes" on this unit SEEM to be connected to the junction box via a plate that all (5) of them are attached with. Each tube has an o-ring on the end which butts up against a rib on the tube. Then the end is passed through the plate and is held in place when the plate is bolted to the junction box. Is that correct? I'm in the process of trying to find an online tech manual to guide me through the procedure.

Thanks again for the come back.
 

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Thanks for the come back. The hydraulic "tubes" on this unit SEEM to be connected to the junction box via a plate that all (5) of them are attached with. Each tube has an o-ring on the end which butts up against a rib on the tube. Then the end is passed through the plate and is held in place when the plate is bolted to the junction box. Is that correct? I'm in the process of trying to find an online tech manual to guide me through the procedure.

Thanks again for the come back.
A photo would help but I think it should be similar to this. I was thinking the nipples threaded into the block (steering valve) but I must be thinking of the auxiliary valve. Here is an example of what I have typically seen. I mean no disrespect and yours could be different. I think what you are calling the o-ring is a (metal ferrell) that push’s against the rib (flare) on the tube and threads onto the nipple. The hose in my photo with the JIC end on it will seat on the nipple, no problem. The ones I have worked on have the same nipple at the other end as well.


This is off of a 318 but my 1800UV is basically the same. I hope this helps.
 

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Discussion Starter #5
Below is a link to a drawing of the junction box assembly at the base of the steering column. I've never seen one of these tubes other than while attached to the "box" so I don't know what type of connection it uses. It's difficult to tell in the drawing but you can't see any kind of a threaded connector when looking at them mounted on the mower. That's why I figured the lines are connected by the plate they pass through. I'll try and get a picture of it mounted on the mower.

http://jdpc.deere.com/pimages/MP62/MP62286________UN06JUN05.gif
 

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The lines have a flange where they slide into the steering valve. Ahead of that flange is an o-ring. The retaining plate butts up against that flange and keeps the line in place. Same setup is used on the 425,445 ect. Just remove the plates, slip the lines out and replace the o-rings. Use o-rings from Deere as they seem to be a weird size.

Sent from my LGL52VL using Tapatalk
 

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It’s always good when the professionals show up.:good2:

Looking at this design it appears there is no way to substitute hoses. Am I correct on that? This minor job looks like it could be a major one depending on which steel line is leaking.
 

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The lines, if they are bad, will need to be OEM. Most of the time it is just an o-ring. Do em all. Once disturbed they will all leak. It's not a job you want to do twice.

Sent from my LGL52VL using Tapatalk
 

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Discussion Starter #9
Thanks to the both of you for the come back. Unfortunately one of the lines has a small hole or split in it. Can't tell until I remove it but it's definitely leaking. Really weird because the line isn't rubbing on anything. On the pictorial drawing it's part #21 (106472), lower line on the right. Do you know if I can finagle the line out and back in while the mower is setting on the floor or will I have to raise it a few feet? I was hoping I'd only have to replace the one o-ring on the line that's leaking but your right, I don't want to do this job twice. As usual Mr. Deere is QUITE proud of his OEM parts. Looks like it'll be around $35.00 in o-rings alone. I'll post an update when I return from "the belly of the beast."
 

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Discussion Starter #10
Update on the cost of the o-rings. I always check ebay for parts and figured they'd have a pretty good deal since OEM John Deere parts are seldom a bargain. Not so this time. I was seeing prices over $5.00 for (1) o-ring thus my estimate of $35.00 for o-rings alone. Had to call the local JD dealership to order the hydro line anyway so I asked about the o-rings too. Would you believe $.75 each. I only need (5) but felt like buying (10) at that price. Moral of the story .... SHOP AROUND .... you may be surprised how much money you can save.
 

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Discussion Starter #11
I'm about to finish the hydro line install, just a couple of things to do and the neighbor will be using it again. When I removed the steering column I did not mark which bulbs went to which socket. Can someone help me out with this? I've searched online but can't find a wiring diagram for the "idiot lights."

One more thing I'll mention that will help anyone who may be faced with this project in the future. When replacing part #AM106472 on a model F725, raise the back end and route the line from the rear of the tractor. You'll be time ahead by removing the deck, left front wheel, seat and brake pulley too. It would be VERY helpful if there are two people working on it. And think after you finish the job you will agree with me when I say I will not be sending the guy who engineered this set up a Christmas card.
 
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