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NAA Hydraulic Relief Valve

Rick Demkovich
NAA Hydraulic Relief Valve

Hi all. been reading a while and finally thought I would make my presence known. I am trying to use a 3 point Deere 2 btm 16" plow on my NAA. Just picked up the plow, so this is a new use for the tractor. I think it might be too heavy, or the relief valve needs replacing, or both. I have been using my tractor with a scraper blade (no problems), a rear scoop (ditto), a pull behind bush-hog, and a 6 1/2' disc. But...three times now in the past couple of weeks I have blown a hydraulic pump gasket while raising this plow. The tractor will pull it fine, BTW. I noted at an auction this weekend that the Ford plows (there was a nice 2 bottom Dearborn there, next to a similar Deere much like mine, and a IH that was converted to 3 pt from Fast Hitch) are much lighter in construction than the Deere. Should have bought the Dearborn but I had to leave before it came up...
Anyway, I presume that since no one else has mentioned a relief valve problem or a hydraulic pump gasket failure that it is a fairly rare occurrence, and that the combination of a slightly faulty valve and an extra heavy tool on the back did it. Also BTW, the lift ran great before...no drop down, and no stuttering when lifting.
So has anyone replaced this valve? Looks like I will have to take off the top cover as well as the hydraulic lines from below. The book says to push it out from the top then put the new one in from the underside.
Comments or suggestions would be highly appreciated.

Rick Demkovich
Re: NAA Hydraulic Relief Valve and the suspect plow

here's a pic of what I am trying to use...Thanks

Jim Loveridge Just from the photo it doesn't look too heavy to lift. I lift my rotery mower which looks a lot heavier then your plow with no problem. Maybe it was just time for the relief valve to give up. Let us know if that was it or not.
Rick thanks, Jim. I already got the relief valve. I was hoping there was some way to remove it from the bottom of the tractor, via the tubing manifold, since that's how you put it in. I will likely rebuild the pump tomorrow and lay off lifting heavy equipment until I can schedule a down day.
I spent the day behind a joystick on a Gehl tracked skidster leveling a new septic field and then crashing down brush. quite a bit different than the Ford!

Larry That tractor should have no problem with that 2 bottom plow. First tractor I farmed with as a boy was a Jublie and it lifted a 2 bottom with no problem. Looks like a nice tractor and plow. Hope you get it figured out.
Jim Loveridge Rick, I'm interested in your re-building the pump. Does your NAA still have the original vane type pump on it? I've been under the impression there were no re-build parts for that pump.
Rick Jim: The tractor has the piston pump, so parts are available, and with a clean workbench and care to not lose the balls or small springs, it is pretty straightforward.

Yesterday I took the pump off and redid the blown gasket and put it back on (I am getting pretty good at this part.). Then filled the reservoir and this morning spent some time getting air out of the lines (bled the system by installing a 3/8 pipe nipple in the pump fill port, and 6' of vinyl hose with a clamp to the nipple, then the end of the hose back into the reservoir. Pump pumps good.) But I will have to drain it again to replace the relief valve, next couple of days. That valve has apparently failed completely, since there is barely enough lift strength now to hold me up, let alone a plow. I did put the disk on since I had to get a field ready to plant, and I didnt need to hold the disc up in the air.
It occurs to me that one way to remove and replace the valve might be to tap the hole in the valve from below once the pump manifold is off, and thread a screw into it, then use the screw and a block to jack the thing out. (maybe you can tell I am a bit squeamish about opening up the top?)
More when it happens.

Jim Loveridge Rick, thanks for the up-date. It sounds like you're quite inventive. We need to be, to work on these old tractors. Interesting way to bleed the system. My '54 still has the vane type pump and I have had good luck bleeding it by just forcing air into the dip stick tube with the return tube loose at the pump. Let us know if your idea for removing the valve works. It would be a great trick to know.
Rick I removed the pressure relief valve the way the manual says: took off the lift cover, removed the tubes from below, and drove the valve out. Took some driving, with an oak dowel and a big brass hammer. Once loose, though it fell right out. Pushed the new one in from below, and tapped it into place with a large punch. Then I dropped the baffle in the farthest, darkest corner of the reservoir and had to go home to find my magnet-on-a-stick to get it out.
Took a 45 minute trip this morning to our friendly Ford/NH dealer to get a new lift cover gasket.
Luckily my son showed up after I got back and we gingerly put the lift cover in place. It is heavy and ain't no place to hold it, but we managed to avoid crushing fingers. Re-filled the oil, then bled the system...but it looks like the lift cylinder and/or cylinder safety valve need work, since while the system lifts nicely, it hiccups at both ends, and it bleeds down right away when you shut the tractor off and leave the lift at the top--even without a load.
So...I am ordering a kit of gaskets and o-rings and a new cylinder safety valve...likely will do the rebuild Tuesday when the parts come.
Does this sound like the right stuff?
BTW, this has occupied my time so much I dropped off the carb from my old Cub Cadet at a small engine shop for THEM to rebuild--at least I can yell and blame someone else if its not right.

rick well, back again and stumped.
got my gasket and o-ring kit, and a new cylinder relief valve. Took the top off again, replaced the valve (slightly different from mine, but Steiners assured me it was the right one), pulled the piston and replaced the o-ring (leather washer still good), replaced the other o-rings throughout. Pulled the control valve and the check valve and verified they were fine, and put in a new o-ring. replaced the rubber washer on the cylinder. replaced the gaskets between the cylinder and lift cover body, and put everything back together. Started it up and pulled it out of the garage and on the driveway, and waited a few minutes for fluid to get moving and the pump to re-prime. flipped the lever from "draft" to "position" control, and lifted the lift handle. Almost immediatedly got a small leak, that turned into a big one, from about the same place on the pump--between the main casting and the end bell. I will take the pump apart again, and replace that gasket, but what the heck!!!
Can anyone shed light on this? I could suspect a couple of things: 1. there is some seam or nick on the pump casting that allows high pressure to blow through even though everything else is okay (hope not, though) or 2. there is some blockage or cocked something somewhere that just will not move and pumps the pressure of the system way up.
Help!

Frank Giambattista I have a Ford 8N with a front end loader it not working I was in 3rd gear coming in from a field and the bucket sprong and drop and hit the ground. I quickly put the cluch in and stop the tractor droped the bucket and backed up to ingage the bucket again when I went to left the bucket I had no hydralic pressure to the bucket or the 3 point hitch. I can't hear the pump and it inside the trani case. I added more fluid and still nothing, did the hydralic pump go?


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