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Discussion Starter · #1 ·
Hey! I’ve got a 3910 that everything seems to be a bastard on. Had it for a couple of years with no problem. Recently lost hydraulic pressure. Ordered a new seal kit & pulled it apart. Mine has a 3.5” cylinder. EVERYTHING I can find for a 3910 is 3”..I can’t even find a 3.5” in any ford. I think it’s an 84 model but even my serial numbers are hard to find info on (BC37048). Any help would be greatly appreciated.
 

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Kubota M9540, Ford 3910, Ford 555A, JD2210
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As usual, I can't remember chit. I rebuilt mine. Can't remember the diameter of the lift cylinder. I'll do some searching back thru my information and see what I come up with.

When you say "lost hydraulic pressure" do you mean your rear remotes won't work either? If the 3pt lift isn't working that might be exclusive to the cylinder you are addressing. If the rear remotes won't work then it may be a hydraulic pump problem? The pump provides "power" to the 3pt first, then to the rear remotes. If you don't have the 3pt in a "work" situation, the rear remotes will work fine. They will work fine even if the 3pt cylinder is completely bypassing. Only way the 3pt affects the rear remotes is if the control lever puts it in a work situation.

To test, I'd drop the 3pt lever to the bottom. Then I'd activate a rear remote circuit and see if it functions? If it does, the problem is not your hyrdraulic pump. If it does not, the problem is the pump.

Hope this helps. Report back with results.
 
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As usual, I can't remember chit. I rebuilt mine. Can't remember the diameter of the lift cylinder. I'll do some searching back thru my information and see what I come up with.

When you say "lost hydraulic pressure" do you mean your rear remotes won't work either? If the 3pt lift isn't working that might be exclusive to the cylinder you are addressing. If the rear remotes won't work then it may be a hydraulic pump problem? The pump provides "power" to the 3pt first, then to the rear remotes. If you don't have the 3pt in a "work" situation, the rear remotes will work fine. They will work fine even if the 3pt cylinder is completely bypassing. Only way the 3pt affects the rear remotes is if the control lever puts it in a work situation.

To test, I'd drop the 3pt lever to the bottom. Then I'd activate a rear remote circuit and see if it functions? If it does, the problem is not your hyrdraulic pump. If it does not, the problem is the pump.

Hope this helps. Report back with results.
I think you got that backwards. Oil flow goes through the remote valve first, and reaches the lift system last. At least that's what I've found on all the Ford utility type tractors I work on. I'm not sure how your 3910 would be any different.
 

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Discussion Starter · #4 ·
Hey! It would loose pressure to the 3pt especially once it heated it up. With implements on it wouldn’t lift, if it was free it would go up and down. Pump seems to be good. When I pulled the cylinder the seals were flat and worn pretty bad so I’m pretty sure it was blow by. But now I can’t find a seal/back up washer in 3 1/2
 

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Hey! It would loose pressure to the 3pt especially once it heated it up. With implements on it wouldn’t lift, if it was free it would go up and down. Pump seems to be good. When I pulled the cylinder the seals were flat and worn pretty bad so I’m pretty sure it was blow by. But now I can’t find a seal/back up washer in 3 1/2
I see your point. What shows up for most everything is a three inch piston, until you get into larger tractor models at four inch plus. I think If it were me, I would probably go to a hydraulic supply. I have no doubt that an O ring and backup to fit can be sourced. I have a place I frequently go to for hydraulic cylinder repair parts. They stock piston seals, O rings, back ups, shaft seals, wipers etc for just about any cylinder out there. Just because New Holland doesn't list it for that model doesn't mean you can't get it.
 

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On the other hand...
I have a lift cover here from a 4000 Ford and the bore on it is ~ 3.310".
Your tape measure looks like it is Not reading 3.5 "but more like about 3.3".
So a piston and seals for your 3910 is probably the same as for a 3 cylinder 4000, 4600 and all derivatives of those models and is readily available.
It really helps to have a better measuring tool by the way. A cheap dial calipers can be bought for about $30. Then use that tape measure for measuring doors and windows on your house.

:oops:
 

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Discussion Starter · #12 ·
Funny enough, it actually mic’s about .002 less than 3.5”, however the measuring tape tends to be easier to read for the illustration purposes. Our 4000 runs a smaller 3” lift piston and our 5610 runs a 4.125. Darndest oddity I’ve seen
 
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