naa hydraulic problem. I NEED HELP!

841operator

New User
I have a 1954 naa ford tractor that I have been working on for probably 2 weeks now. I have rebuilt the pump, I have rebuilt the cylinder, and I've installed all new gaskets on the lift cover. I took off the inspection cover and seen fluid leaking from the front of the cylinder that would be the front of the tractor. it looks like to me the fluid is coming from the metal plate that holds the spring to the control valve. If I rev the tractor up the arms will raise but if I stand on them it wont. After they are raised they don't bleed down. Is there an o ring on the control valve? Should it be running out around the spring ? It looks a little pitted, but I don't think it should Pou out like it does.
 
Which pump do you have? Piston of vane? Is the back pressure valve stuck? "Under the Acorn nut on the right side under the quadrant" I would think if the pump is pumping full volume, oil would be splashing out the plate. If so the unloading might be stuck
 
(quoted from post at 15:35:25 08/22/15) I have a 1954 naa ford tractor that I have been working on for probably 2 weeks now. I have rebuilt the pump, I have rebuilt the cylinder, and I've installed all new gaskets on the lift cover. I took off the inspection cover and seen fluid leaking from the front of the cylinder that would be the front of the tractor. it looks like to me the fluid is coming from the metal plate that holds the spring to the control valve. If I rev the tractor up the arms will raise but if I stand on them it wont. After they are raised they don't bleed down. Is there an o ring on the control valve? Should it be running out around the spring ? It looks a little pitted, but I don't think it should Pou out like it does.
he hole in picture surrounded by the 3 bolts: only a small "burp" of fluid comes out here and only when the unloader valve moves into unload/bypass mode (that is from lift to either hold or lower).
 
(quoted from post at 06:06:58 08/23/15) Which pump do you have? Piston of vane? Is the back pressure valve stuck? "Under the Acorn nut on the right side under the quadrant" I would think if the pump is pumping full volume, oil would be splashing out the plate. If so the unloading might be stuck
have a piston type pump. The only thing I didn't replace is the o ring on the unloading valve. I believe the back pressure valve is functioning. If I remove the acorn nut it will leak a small amount of fluid. I made a gasket out of leather that seems to word good.
 
The plate on mine is different than that one. Mine has an opening on the end of the control valve that has a spring that sets between the thin plate and the control valve.
 
(quoted from post at 20:41:45 08/23/15) The plate on mine is different than that one. Mine has an opening on the end of the control valve that has a spring that sets between the thin plate and the control valve.
K, I took 841 in your handle as tractor vs stated NAA. So, it looks like this , I presume. If not, maybe baffle plate missing? On the NAA, that hole is also where the cylinder dump exits during lower. Can you alter the flow there by moving the touch control lever position?
 
That is the same as mine. If I pull the lever in the up position it will decrease the amount coming out of the dump hole a little.
 
(quoted from post at 18:53:57 08/23/15) That is the same as mine. If I pull the lever in the up position it will decrease the amount coming out of the dump hole a little.
I looked at it a little closer and the one I have is slightly different. I'll try to post some pics tomorrow.
 
(quoted from post at 21:56:19 08/23/15)
(quoted from post at 18:53:57 08/23/15) That is the same as mine. If I pull the lever in the up position it will decrease the amount coming out of the dump hole a little.
I looked at it a little closer and the one I have is slightly different. I'll try to post some pics tomorrow.
The only thing I didn't replace is the o ring on the unloading valve." An unloader O-ring leak would exit there too, so at this moment, I would have that high on my suspect list.
 
Gasket is blown under the ram cylinder.

Be sure to replace all three gaskets when you repair.

Must be same thickness on all three.

One long gasket and two small round gaskets.

Zane
 
I checked the cylinder gaskets and they looked good but I got to thinking that maybe it wasn't getting enough pressure past the first relief valve. I noticed the fluid at the bottom is very active when the tractor is at high rpm's. I grabbed me a screw driver and started tightening the flat head screw on the valve that's at the bottom of the housing. I tightened it a little at a time, now it will lift me if I stand on the arms. Would anyone agree I would have a weak spring on the relief valve? I might have to fork out the 92 bucks on the valve.
 
(quoted from post at 10:33:50 08/25/15) I checked the cylinder gaskets and they looked good but I got to thinking that maybe it wasn't getting enough pressure past the first relief valve. I noticed the fluid at the bottom is very active when the tractor is at high rpm's. I grabbed me a screw driver and started tightening the flat head screw on the valve that's at the bottom of the housing. I tightened it a little at a time, now it will lift me if I stand on the arms. Would anyone agree I would have a weak spring on the relief valve? I might have to fork out the 92 bucks on the valve.
ound the problem, it was a dirty pump relief valve. The tractor will hold the load and not bleed off quick anymore. I had that cover on and off probably 15 times looking in the wrong place and after enough reading from this sight finally found it. Thanks a bunch for taking time to help me. I'm gonna be watching for naa problems so maybe I can offer some of what I learned.
 
(quoted from post at 11:39:58 08/28/15)
(quoted from post at 10:33:50 08/25/15) I checked the cylinder gaskets and they looked good but I got to thinking that maybe it wasn't getting enough pressure past the first relief valve. I noticed the fluid at the bottom is very active when the tractor is at high rpm's. I grabbed me a screw driver and started tightening the flat head screw on the valve that's at the bottom of the housing. I tightened it a little at a time, now it will lift me if I stand on the arms. Would anyone agree I would have a weak spring on the relief valve? I might have to fork out the 92 bucks on the valve.
ound the problem, it was a dirty pump relief valve. The tractor will hold the load and not bleed off quick anymore. I had that cover on and off probably 15 times looking in the wrong place and after enough reading from this sight finally found it. Thanks a bunch for taking time to help me. I'm gonna be watching for naa problems so maybe I can offer some of what I learned.
ell be cautious with the advice. "Found the problem, it was a dirty pump relief valve. The tractor will hold the load and not bleed off quick anymore."

....Because, the pump relief valve has zero bearing on whether the lift will "hole up"/not leak down or not.
 
I should have worded that a little better. After I rebuilt the cylinder, cleaned all the passages, installed all new o-rings, changed the fluid, and a brand new lift cover gasket it would hold the lift arms but spew oil from the back of the cylinder and it had no lifting power. I then [ after multiple times of removing the cover] pulled out the pump relief valve and inspected it. I had previously disassembled the relief valve didn't see anything obvious and forgot to reinstall the tiny flat washer at the bottom of the valve. I removed it again and closely inspected it and found the small spring was clogged with junk and I had to make a new washer with a nail head that I shaped to fit the diameter of the valve. [/code]
 
Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
 
(quoted from post at 09:10:56 08/28/15) Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
The one at the belly. The one on the cylinder looked to be in great shape.
 
(quoted from post at 12:13:23 08/28/15)
(quoted from post at 09:10:56 08/28/15) Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
The one at the belly. The one on the cylinder looked to be in great shape.
eason for questions is that I'm really having a hard time connecting your cause/effect. For example, the early on stated 'problem' was excessive fluid coming out of front of cylinder at plate/dump port/hole. Now, the solution as the pump relief valve in belly of tractor. ???????????????
 
(quoted from post at 09:52:53 08/28/15)
(quoted from post at 12:13:23 08/28/15)
(quoted from post at 09:10:56 08/28/15) Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
The one at the belly. The one on the cylinder looked to be in great shape.
eason for questions is that I'm really having a hard time connecting your cause/effect. For example, the early on stated 'problem' was excessive fluid coming out of front of cylinder at plate/dump port/hole. Now, the solution as the pump relief valve in belly of tractor. ???????????????
I'm thinking the fluid was flowing at high pressure through the pump relief valve with low restriction because i initially forgot to reinstall the small round plate at the base of the valve causing it to flow through the cylinder housing and out the sump.
 
(quoted from post at 10:36:22 08/28/15)
(quoted from post at 09:52:53 08/28/15)
(quoted from post at 12:13:23 08/28/15)
(quoted from post at 09:10:56 08/28/15) Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
The one at the belly. The one on the cylinder looked to be in great shape.
eason for questions is that I'm really having a hard time connecting your cause/effect. For example, the early on stated 'problem' was excessive fluid coming out of front of cylinder at plate/dump port/hole. Now, the solution as the pump relief valve in belly of tractor. ???????????????
I'm thinking the fluid was flowing at high pressure through the pump relief valve with low restriction because i initially forgot to reinstall the small round plate at the base of the valve causing it to flow through the cylinder housing and out the sump.
Does this sound right to you? I would like to know your opinion and I would like to correctly diagnose the problem.
 
(quoted from post at 10:36:22 08/28/15)
(quoted from post at 09:52:53 08/28/15)
(quoted from post at 12:13:23 08/28/15)
(quoted from post at 09:10:56 08/28/15) Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
The one at the belly. The one on the cylinder looked to be in great shape.
eason for questions is that I'm really having a hard time connecting your cause/effect. For example, the early on stated 'problem' was excessive fluid coming out of front of cylinder at plate/dump port/hole. Now, the solution as the pump relief valve in belly of tractor. ???????????????
I'm thinking the fluid was flowing at high pressure through the pump relief valve with low restriction because i initially forgot to reinstall the small round plate at the base of the valve causing it to flow through the cylinder housing and out the sump.
Does this sound right to you? I would like to know your opinion and I would like to correctly diagnose the problem.
 
(quoted from post at 20:47:15 08/28/15)
(quoted from post at 10:36:22 08/28/15)
(quoted from post at 09:52:53 08/28/15)
(quoted from post at 12:13:23 08/28/15)
(quoted from post at 09:10:56 08/28/15) Are you speaking of the ram cylinder relief valve attached to top cover assembly OR the pump relief valve in the belly of the tractor's hydraulic cavity?
The one at the belly. The one on the cylinder looked to be in great shape.
eason for questions is that I'm really having a hard time connecting your cause/effect. For example, the early on stated 'problem' was excessive fluid coming out of front of cylinder at plate/dump port/hole. Now, the solution as the pump relief valve in belly of tractor. ???????????????
I'm thinking the fluid was flowing at high pressure through the pump relief valve with low restriction because i initially forgot to reinstall the small round plate at the base of the valve causing it to flow through the cylinder housing and out the sump.
Does this sound right to you? I would like to know your opinion and I would like to correctly diagnose the problem.
o, I'm sorry, it does not sound right. Pressure only builds due to a restriction, typically the load on the lift is that restriction.. With open flow, there is no pressure on a pump outlet.
 

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