Ford 9N 3-point problem

[PoochyCor]

The 3-point on my Ford 9N has continually weakened to the point that it lifts just a few inches. If I put the tractor in neutral and let it run it'll eventually lift maybe a foot. Any ideas of the problem and advice on the repair?

 

[mostly_gas]

Have you checked the oil level in the trannie? Does it matter how much weight is on the 3pt when you try to raise it? Does it hold when you shut the tractor off without moving the lift lever?

 

[Jerry/MT]

The 3-point on my Ford 9N has continually weakened to the point that it lifts just a few inches. If I put the tractor in neutral and let it run it'll eventually lift maybe a foot. Any ideas of the problem and advice on the repair?

Most failures to lift on those hydraulic systems are due to a leaking lift cylinder, a leaking supply tube from the pump to the cylinder, stuck open relief valve, a leaking pump side plate, or possibly the control valve not moving forward completely due to sticking conditions.

Pull the side plate off the right hand side and start the enegine with the pump(pto) engaged. UNDER NO CIRCUMSTANCES PLACE YOUR HAND INTO THE HYDRAULIC COMPARTMENT WITH THE ENGINE RUNNING! Place the lift lever in the full up posiotion. Using a flashlight, look up under the lift cover at the lift cylinder for a leak. Anything more than a few drops is leak. using a mirror, look at the right front corner of the hydraulic compartment. You should see a metal tube running vertically. look for fluid squirting from a crack or streaming down the pipe from a blown o-ring seal on the lift cover. Next look at the pump. Is there fluid coming outof the joint beween the main body and the side plate? (leaking side plate gasket) Is there a lot of turbulence and noise coming from the where the "H" shaped control fork goes into the fluid?(Stuck open relief valve). Finally, shut down the engine. reach down in the fluid and feel for the "T" shaped control valve stem attached to the "H" shaped control fork. Push forward on the "T" shaped stem. Then pulll back. The total motion should be near 1 inch. Now push the control stem all the way forward ( this ets the cntol valve to lift) and start the tractor with the pto engagedand the lift lever full up . Does the lift rise? If it does the control valve is sticking.

Do these checks and then get back with the results.

 

[Soundguy]

excelent post by jerry.. saved me a whole bunch of typing too

 

[PoochyCor]

Thanks for the help. Jr high football tonight but I'll run the check tomorrow and post results.

 

[Soundguy]

looking forward to hearing back from you.

soundguy

 

[Jerry/MT]

excelent post by jerry.. saved me a whole bunch of typing too

I think i need to go back to some old posts on these type of problems and "copy & paste"! Saves a lot of typing.

 

[Soundguy]

i have some saved over at ytmag. the common genny/vreg questions.. or 'how do I wire up a lamp' type questions..

 

[PoochyCor]

Life has taken over for a few days but I'll get back to the tractor soon. I'll post when I do.

 

[Bob419n]

I bought a 1941 9n and I rebuilt my hydraulic pump because the right side plate had broke. I bought a kit with every thing for the pump including right and left plates and new relief valve. It still will not lift any weight. If I lift the blade by hand it will stay up and only loose 2 to 3 inches in 24 hours. I have checked every thing and can not figure out why it will not lift the blade

 

[Soundguy]

wow, you resurected a 3 year old post to post your new question.

Many people will likely NOT see it.

In any case. you say you have rebuilt your pump, including a new relief valve.

have you pressure tested it? IE... chain lift arms down and plumb a gauge into the test port at the rightfront of the base of the pump using an ORB fitting. . that port is NOT pipe thread.

My guess is you are not building pressure int he pump due to ill fitting parts valves/springs..e tc.

 

[Stimw]

I rebuilt one of those pumps once and I don't remember if it was on the 8 or the 9-N that I owned. ???
That Scotch-Yoke pump is the WEIRDEST hydraulic pump that I have ever seen!! What were they smoking??

 

[Bob419n]

There is a threaded port at the right front of the pump that is connected to the tube that feeds the cylinder. can i pressure test it from there? and how much pressure should it have?

 

[Soundguy]

There is a threaded port at the right front of the pump that is connected to the tube that feeds the cylinder. can i pressure test it from there? and how much pressure should it have?

Just like my post #11 said... ( i'll re-quote it here since it was not read or ignored )

have you pressure tested it? IE... chain lift arms down and plumb a gauge into the test port at the rightfront of the base of the pump using an ORB fitting. . that port is NOT pipe thread.

1500-1700-psi is expected pressure.

 

[Jerry/MT]

Chances are the control valve is not moving properly when commanded by moving the lift lever up. The valve could be sticking or the "T" shaped valve actuator rod is broken or is not in the sockets on the "H" control fork. I'm assuming you have no leaks in the system and that sounds like a good assumption since you say it drops 3-4 inches in 24 hours. That implies pretty low system leakage. Also see my post above.