hydraulic pump D-14

Well, approaching the end of 9 months of work on a total d14 rehab. Yesterday, installed the newly painted gas tank, finished wiring took
a deep breath and hit the starter button. Motor sprung to life and is purring nicely. Happy moment . However, some despair quickly entered. About the only
thing i didn't touch on this tractor was the hydraulic pump. The lift arms are stuck up, and there apparantly is so much pressure in the pump that it actually
blew the glass out of the new traction booster dash gauge. So, i'm guessing that this pump's unloader valve is stuck, or the rest of it needs to be rebuilt. I
have a shop manual, and can probably follow along, but wondering if anyone has tips on which parts to purchase and any secrets to a successful rebuild. Thanks for
any help.
It's not unusual for the lift arms to be stuck up, even with the engine off and the hydraulic pressure released. Have you tried to push them down with any force? I think I would plug off the gauge line and try it again. Maybe those new gauges aren't what they used to be?
Thinking the same thing about the gauge. Yes, i've applied some pressure to the lift arms but they don't want to budge .
Not sure what to do here. i doubt the pump has ever been rebuilt, and with just a screen for a filter i can see how/why there
could be junk in the valve body. Again, just trying to figure out where to go with this .
Usually you can hear the unloader valve unload. And you can feel the pressure relief in the lever when you pull it down. Did you experience any of that? It's been many years since I worked on them. It was common to be working on the WD style pump, but seldom do I remember getting into a D series pump. Same basic pump, but different. They're so much older now, who knows?

Have you tried loosening the line at the transport valve to see if there's really pressure on the lift arm cylinder? Be careful!
bob - no, i can't feel any pressure relief when the lever is put in to the lower position.
i just found this all out yesterday, so have not had a chance to loosen the hydro line and
let any fluid run out. Given these pumps have very little filtering, won't surprise me if one or more of the valves
are stuck.
Let's start some diagnosis. Both Hydraulic levers need to be fully DOWN or horizontal. The longer Lift/Lower lever should be able to go lower than horizontal. Under the belly of the tractor, there is a link rod that connects to the drawbar linkage and then forward to the hydraulic pumps sump. The linkage is there?? YES or NO ?? It must be there or the pump is turned on all the time. If the link rod is there, loosen the front nut forward with a 3/4" open end wrench to the end of the link rod. Move the rear nut forward until it won't go any farther. Try your hyd pump again.
Very appreciative for your comments. Yes, the parts u mention are
on the tractor so Ill try this drill tomorrow. Decided too reinstall
the original seat instead of a replacement. I already had put about
5 hours of work in to it (weld pan cracks, new sock, bushings, pins
and of course paint), so figured I might as well use it instead of
store it. Pleasantly surprised at how comfortable it is . Thnx again
for help
doc - went out just now and did the steps above. That helped a ton. For sure turned off the hydo pump. The rear end of the tractor is now super quiet from it not
running. So now, just have to figure out why my lift arms are stuck up, and i think the hydraulics will pass the test. down to painting the add-on hitch assembly,
2-part hood, and front bonnet, finish the lights, and i'm done. Thing is lookin pretty cool.
One last follow up on this - really for Dr Allis - Back to shop again this am - started playing with the
hydraulic linkage and discovered my lift arms would fall just fine - secret was the adjustment of the screw/spring
under the fuel tank. I pulled the lift lever well below horizontal, and bingo - lift arms slowy went down. Awesome .
So, a little adjustment to the linkage and no need to pull the pump. A rare break! Thanks again Doc for the info-
lower linkage adjustment started this all off.
The proper adjustment hasn't been done just yet. I wanted to prove to you and me that this was the problem. So, I've basically shut the hyd pump off on the Traction Booster circuit, so it is now inoperative. If you want the Tboost system to work, we need to fine tune that sensing linkage. If you have an Owners manual, the steps are listed in it. It begins by adjusting the large nut down below that puts some tension on the drawbar coil spring. Once that is correct, then you readjust what you changed so that when the short TBoost lever is 4 or 5 notches from the very top of it's stroke, the lift arms slowly raise. These two steps must be done in order to make the TBoost system work right. If you have no need for it, it's fine the way it is right now.
When I made the decision to start this rebuild, I spent most hours
disassembling for paint and repair with the probably incorrect
mindset of wrench it off now, read about what it does later Big
Gigantic spring on the bottom of the tractor? Ahh , pull it to paint ,
figure out what it does later. Now 85% painted, and running,
starting to find things like the traction boost. Put the big spring
back on maybe 5 months ago. Both linkage nuts were way loose
(thank u doc allis post), so closely studying g shop manual for
These and other fine-tunes . Fascinating to me all of the work and
Effort allis put in to this stuff many years ago
Like I say, that big coil spring needs to be under a certain amount of tension, as per the owners manual. Being a little tighter is better than looser because when the drawbar gets a yank on it the linkage to the pump gets activated. Spring tension first. Link rod length second.
yup - manual says to start there first with a certain amount of preload. did that yesterday, then got sidetracked with a fitting leak
on the power steering pump. back to fine tune today. Doing back flips of joy that i do not need to pull the hydro pump and do a rebuild.
For the record - i learned one hard lesson on the rebuild - i really liked the white steering wheels that i think were put on the 15's and i think
later 14's . looking at the parts manual, needed to find a splined steering wheel shaft. found one for 20 bucks on someone's part site. installed in the
reassembly. bought a wheel from dj's , and at assembly realized the base of the wheel is much wider than the original and won't clear the infamous traction
booster lever. ugg. re-cheecked parts manual and didn't realize the support base for all of this is a different part number. SO, back to the black wheel .
outside of that malfunction, most everything else has bolted up nicely. Only other thing so far that i am nervous about is the power steering . total overhaul. i
have total range from right to left, no leaks and nice assist, but when i change from left to right, i feel a little resistance, almost like it's being held.
starting to look in to that today. thanks doc - learned much from your tip - one of the best i read was the oil thru the filter trick to prime the oil pump. i had
to do that too.

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