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GunPilot
11-03-2007 11:00:50
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All -
After getting my '49 8N going, I was able to raise the lift arms, but they would not lower. After a while I was able to lower them but now they won't raise. I've searched the archives and read up on this and have about concluded that I need to pull the pump and make sure the valves aren't clogged.
However....
With the dipstick side cover off, when I move the position control lever, I see that the rod that moves the control valve hardly moves back and forth at all. The movement is mostly up and down, which barely moves the valve rocker at all. A fraction of a millimeter. I can reach in and move the valve by hand. It moves a lot to the rear - that is toward the rear of the tractor, but seems to be pushed fully to the front.
My question is, what is normal movement of the control rod? Here are some more details:
The hydraulic pump worked previously, even before the resto. The lift I cannot say because the tractor did not come with lift arms and the lift had not been used in decades because it had an Everett trencher on it. The pump functioned because the tractor had a front blade that would raise and lower. Now, I cannot get hydraulic pressure at the port that the blade was previously hooked to.
The rod is not bent.
I rebuilt the lift cover because the cylinder was corroded out from years of non-use. It's possible I goofed the assembly so the control rod doesn't work but I don't see how.
There is no leakage inside when the pump is operating. It has a new NAA piston with the new cylinder.
There is no excessive turbulence around the relief valve. I did pull the pump and clean the sludge out of the cover area, and checked the relief valve, but did not replace it. I did not disassemble the pump.
The PTO is turning the pump and the pump has its proper movement.
Here's what I'm contemplating:
1. The valves in the pump are plugged from debris and sludge that got stirred up as a result of the rebuild. I tried to remove as much as possible but there was certainly areas that not all of it came out of.
2. I may have botched the assembly of the lift cover so that the control rod is not moving correctly.
So, I'm going to pull the pump, disassemble it and clean it. I'll reinstall it and see if the problem is cured. If not, then the lift cover comes off and I guess I'll look at that again.
Any thoughts, or checks I can make to save me pulling the lift cover?
Here's a link to a pic of the lift cover after I reassembled it. I know the pic is huge but I wanted the detail shown. Any obvious goof-ups?
Lift Cover Pic
Thanks,
George
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That's an older pic. 
