9n hydraulic issues... Please help!

[Broken S Ranch]

I have a 9n that had a posits too all hydraulic system installed before I bought it. I backed into a hidden stump a few weeks ago engaging the protective spring, which lifted the deck off the ground. After some tinkering with it I was able to unstick the top spring and went back to mowing. Next time I used it, the hydraulics would lift but only while the pto was engaged. Once you pushed the clutch the load would drop. Shortly thereafter it quite working all together. I have replaced the hydraulic cylinder and piston (the old piston ring was bad). This did nothing. I then replaced the control valve and the safety release valve. That seemed to fix everything... for approx 20 minutes. I parked it until this morning. Went out to use my fixed tractor to mow this morning and now the hydraulics wont lift at all again. I becoming quite frustrated. I have to be missing something... probably stupid. The forks are connected, the pump is churning the hydraulic fluid, and the valves and cylinder itself are all new. What am I missing? Please help! Thanks!

 

[Broken S Ranch]

To edit original post; first line is supposed to say that it had positional 8n hydraulics added to it before I bought it. 9n tractor but with positional hydraulics like an 8n.

 

[TheOldHokie]

(quoted from post at 18:16:59 07/26/20) I have a 9n that had a posits too all hydraulic system installed before I bought it. I backed into a hidden stump a few weeks ago engaging the protective spring, which lifted the deck off the ground. After some tinkering with it I was able to unstick the top spring and went back to mowing. Next time I used it, the hydraulics would lift but only while the pto was engaged. Once you pushed the clutch the load would drop. Shortly thereafter it quite working all together. I have replaced the hydraulic cylinder and piston (the old piston ring was bad). This did nothing. I then replaced the control valve and the safety release valve. That seemed to fix everything... for approx 20 minutes. I parked it until this morning. Went out to use my fixed tractor to mow this morning and now the hydraulics wont lift at all again. I becoming quite frustrated. I have to be missing something... probably stupid. The forks are connected, the pump is churning the hydraulic fluid, and the valves and cylinder itself are all new. What am I missing? Please help! Thanks!

• [*:5e2f9019b0]The hydraulics only work when the PTO is running. That is because the pump is powered by the PTO shaft. Nothing unusual about this behavior[*:5e2f9019b0]You need to verify the forks are actually operating the control valve. You can do that by observing the operation through the side inspection cover.[*:5e2f9019b0]You can verify the pump is actually producing flow by removing the plug in the pressure test port and connecting a piece of tube to the port. Run the tube back into the inspection port and run the tractor. When you raise the 3pt lever you should get flow out of the tube. If not the pump is not pumping.[/list:5e2f9019b0]TOH

 

[HCooke]

Still havre to have the pto engaged. The PTO drives the pump.

 

[Broken S Ranch]

Sorry for any misunderstanding. I must not have explained well. When I stated that it wasnt holding the load I meant that it wasnt holding the load up when I pushed in the clutch disengaging the pto, but that isnt normal. Normally you can lift a load, then use your clutch when stopping or shifting. The load has never lowered at that point. Always had good pressure and the load will hold even when the tractor is shut off, at least for quite a while. That morning however it quite holding the load unless the pto was actively on. Shortly there after it quite lifting all together. Since making all the replacements it did work last night for a while. Went back out this morning and it didnt work at all again. The forks do seem to be operating correctly and the hydraulic fluid is churning when pump is engaged as seen through the viewing door. Do you still think I should connect a hose and see if the pump is actually pumping fluid? Can you give me a little more explanation as to where or how to connect that hose to check it? Thanks!

 

[Caryc]

With the right side inspection plate removed and the PTO lever engaged and the tractor running, do you see any fluid coming down from the top cylinder?

If that cylinder is leaking badly, your lift arms are going to drop when you push in the clutch or turn off the engine.

 

[TheOldHokie]

(quoted from post at 19:03:22 07/26/20)
Sorry for any misunderstanding. I must not have explained well. When I stated that it wasnt holding the load I meant that it wasnt holding the load up when I pushed in the clutch disengaging the pto, but that isnt normal. Normally you can lift a load, then use your clutch when stopping or shifting. The load has never lowered at that point. Always had good pressure and the load will hold even when the tractor is shut off, at least for quite a while. That morning however it quite holding the load unless the pto was actively on. Shortly there after it quite lifting all together. Since making all the replacements it did work last night for a while. Went back out this morning and it didnt work at all again. The forks do seem to be operating correctly and the hydraulic fluid is churning when pump is engaged as seen through the viewing door. Do you still think I should connect a hose and see if the pump is actually pumping fluid? Can you give me a little more explanation as to where or how to connect that hose to check it? Thanks!

Just because the forks are moving doesn't mean the control valve spool is moving. Do the pump test - its easy. Connect t the tubing to the pressure test port which is on the lower right side of the base of the pump . There is a hex head plug screwed into the port next to the muffler. It's 1/2-20 thread and for this test you can just push a piece of tight fitting 1/2" OD plastic tube into the port. It may leak a bit so put a drip pan under it and hold the tubec in place so the oil doesn't push it out. You will only get flow with the PTO running and the 3pt lever up. Lowering the lever will shut off the flow. You can even pur the hose in the drip pan rather than the inspection port - just dont let the pump run more than a 10-15 seconds or you will pump a good volume of oil into the pan. If you dont get any flow the pump is not pumping and you likely have a problem with the control valve or linkage.

TOH

 

[Tim PloughNman Daley RIP]

So, you have an aftermarket POSTION CONTROL model such as the Zane Thang? Or, do you mean you swapped out an 8N rear and center with 8N pump? The term 'forks' to me would indicate you have a 9N hydraulic system. Perhaps you should disconnect the Zane Thang for now and get the standard hydraulic system working properly first. Get your ESSENTIAL MANUALS out start reading.

FORD 9N/2N ESSENTIAL OWNER/OPERATOR/PARTS/SERVICE MANUALS:

Tim Daley(MI)