3 point hitch won't stay raised

[ArtilleryVet]

The hitch works off and on.  The other day when I was spreading the hitch stayed at the raised level that I set it at except in one instance when my neighbor dumped the first load of manure from his front loader.  I raised it back up and didn't have a problem with it after that.  Yesterday when I hitched up to the spreader it would not stay up to any level I set it at.  I tried it this morning and the hitch stays up but if you apply pressure to it like standing on the drawbar it lowers.  Any suggestions on what it is?  The manual I have says it may be the check valve but before I go tearing things apart I'd like to know if anyone else has had this problem. 

I'm also trying to figure out what year the tractor is and the plate on the left side of the motor is worn so I can't read the numbers.  Are there any other marking that ford put on the tractors that would help me identify the year?

[Pete P.]

Artilleryvet --

You didn't mention the model of your tractor, I'll assume 9 or 2 N, answer will be similar for 8N ... well we'll get to that.  Also, I'll assume that you lifted the spreader, then disengauged the PTO and left the draft control lever all the way up.

Assuming the above, it may sound obvious but the only way for the lift to lower is for oil to leave the cylinder.  There are several ways that it may do so internally, the most popular seems to be a leaky piston ring, leaky control valve and / or a relief that's stuck open.  I'm betting on the latter because you said the lift was okay 'till your friend loaded the spreader -- if the load hit the spreader hard it would have shock-loaded the hydraulic system.  If the relief popped open (which is its job) and for some reason didn't re-seat it would allow oil to leak from the cylinder back into the sump. 

Folks will tell you that you can pull the right side inspection plate and look for oil turbulance when the pump is running, but I can never see it.  Others say to put your hand in there and feel for oil squirting past the relief (again with pump running) but there's no way I'd put my hand in a running machine.  Best thing in my opinion is to drop the pump and replace the relief -- doesn't cost much and it may fix the problem.  If it doesn't, I'd next pull the top cover and replace the piston ring.  Use a neoprene O-ring vs. the original steel, and inspect the cylinder for any wear.  Replace the pistion and cylinder if you have to.  Upon reassembly pay close attention to the top cover seal because the high pressure oil travels to the cylinder via a tube along the side of the housing which connects to a passage in the top cover -- this will leak mercilessly if your gasket job is not up to the task and will re-create the very problem you're having now.

Hope this helps,

Pete P.
Harborcreek, Penna.

[ArtilleryVet]

Thanks for the help Pete.  My tractor is a 9N.  We bought it from a friend at work who said that it was a 1939.  He bought it from a family in Lancaster who told him it was a 1939.  But the data plate on the motor is so worn that I have no way of verifying unless anyone knows of any other serial numbers on the tractor itself.  I haven't been able to find any. 

I do have another problem.  I replaced the voltage regulator this morning because every time I shut off the tractor the amp meter would read into the negative (usually around 10-20amps).  I would tap the voltage regulator and the needle would go to 0.  When I shut off the tractor today the needle pointed into the negative (Around negative 30amps)  I taped the voltage regulator and the needle went back to 0.  So what other problem could it be if it wasn't the voltage regulator?   

[Pete P.]

Artillery Vet --

The 9N and 2N did not have voltage regulators as such.  They had only a cut out relay (which may be what you're referring to.)  The cutout is a round can looking thing that mounts on the front of the steering gearbox above the clutch compartment.  There is one wire from the one (and only) post on the generator and one wire to the battery.  The function of the cutout is to open the circuit any time the generator voltage is less than the battery voltage thereby preventing the battery from discharging through the generator when the engine is stopped or at idle.  It does not, however, regulate output voltage or current as a voltage regulator does. 

A voltage regulator has two or three relays, one of which is a cut out and is connected to the armature terminal of the generator, the others increase or decrease the voltage applied to the field of the generator -- more field current = more intense magentic field = more generator output.  Generators used with a regulator are of the shunt-wound type which have the afforementioned two terminals (A & F.) 

Sorry for the long answer but yes -- the cutout / regulator is your problem.  Either component is relatively inexpensive so I'd replace it vs. try to dress the points, re-seal the can, etc.

RE: serial numbers -- the engine SN is the only one.  There are a ton of design clues that can put you in the right age range but that's another discussion.

Pete P.
Harborcreek, Penna.