First post here but have learned a lot from these forums so have to say thank you! I will try and make a long story short...
I have a very nice NAA with vane pump that wouldn't lift a heavy load and had a leakdown issue. Hydraulics seemed to work fine other than this. They were responsive and appeared to work as I would expect them to. I removed inspection port and came to the conclusion it was a piston seal. I removed the lift cover and replaced the piston, seals (they were clearly bad) and all gaskets. Lift cylinder was in really good shape. In the process I cleaned everything up nice and changed fluids. Sludge buildup and fluid condition appeared to be in above average shape. What I did not do was loosen the acorn nut prior to removing the lift cover. (mistake #1) I do not think i buggered anything up in the processes and loosened it prior to lift cover removal. When I loosened the threaded tube that holds the back pressure valve, I had a hard time getting it to move backwards. Seemed like i had to get the threaded tube just right for the valve to "snap" into place and stay towards the case. Pretty sure it had enough clearance to put the lift cover back on without messing it up. Note that I did not replace the rubber gasket that seals the valve against the lift cover. It seemed like it was in descent shape but was indented where the valve was pushed against it. (mistake #2?)
After installing the lift cover, I thought i was in good shape. The tractor would not leak down after a couple hours with a dearborne cultivator attached. A week later I attached my mower deck and it would barely lift the front off the ground. I can hear a buzzing sound that I think is coming from the vane pump but this happened before. I also noticed that draft mode would not lift the implement but if i pushed down on the draft control selector, it would raise the implement.
First thing I wanted to check was the acorn nut. I removed it with the tractor running and a steady stream of fluid came out of the hole. I backed out the threaded tube and fiddled with it. I ended up inserting a punch and tapped (gently) to see if I could seat the valve. Sure enough, it popped a 1/16th of an inch. Started tractor and pushed against the valve and the fluid leak stopped. I could hear the seal working when i pushed on it (gently). Installed acorn nut and now the lift works worse than before. I wanted to see if I can get some feedback before I mess with it some more. Hoping that this is the issue and I can take a better look tomorrow. I also want to remove the inspection cover again and check for turbulence by the pressure relief valve on the bottom of the case. Thoughts on this?
I'm thinking (hoping) that I torqued the valve slightly when i tightened the bracket that holds it against the case. I'm also thinking I might have 2 problems here.
Any assistance in troubleshooting this issue ia VERY much appreciated.
Thank you!
-Travis
I have a very nice NAA with vane pump that wouldn't lift a heavy load and had a leakdown issue. Hydraulics seemed to work fine other than this. They were responsive and appeared to work as I would expect them to. I removed inspection port and came to the conclusion it was a piston seal. I removed the lift cover and replaced the piston, seals (they were clearly bad) and all gaskets. Lift cylinder was in really good shape. In the process I cleaned everything up nice and changed fluids. Sludge buildup and fluid condition appeared to be in above average shape. What I did not do was loosen the acorn nut prior to removing the lift cover. (mistake #1) I do not think i buggered anything up in the processes and loosened it prior to lift cover removal. When I loosened the threaded tube that holds the back pressure valve, I had a hard time getting it to move backwards. Seemed like i had to get the threaded tube just right for the valve to "snap" into place and stay towards the case. Pretty sure it had enough clearance to put the lift cover back on without messing it up. Note that I did not replace the rubber gasket that seals the valve against the lift cover. It seemed like it was in descent shape but was indented where the valve was pushed against it. (mistake #2?)
After installing the lift cover, I thought i was in good shape. The tractor would not leak down after a couple hours with a dearborne cultivator attached. A week later I attached my mower deck and it would barely lift the front off the ground. I can hear a buzzing sound that I think is coming from the vane pump but this happened before. I also noticed that draft mode would not lift the implement but if i pushed down on the draft control selector, it would raise the implement.
First thing I wanted to check was the acorn nut. I removed it with the tractor running and a steady stream of fluid came out of the hole. I backed out the threaded tube and fiddled with it. I ended up inserting a punch and tapped (gently) to see if I could seat the valve. Sure enough, it popped a 1/16th of an inch. Started tractor and pushed against the valve and the fluid leak stopped. I could hear the seal working when i pushed on it (gently). Installed acorn nut and now the lift works worse than before. I wanted to see if I can get some feedback before I mess with it some more. Hoping that this is the issue and I can take a better look tomorrow. I also want to remove the inspection cover again and check for turbulence by the pressure relief valve on the bottom of the case. Thoughts on this?
I'm thinking (hoping) that I torqued the valve slightly when i tightened the bracket that holds it against the case. I'm also thinking I might have 2 problems here.
Any assistance in troubleshooting this issue ia VERY much appreciated.
Thank you!
-Travis
