3-Point Hitch 3 Point Hitch Problems?

   / 3 Point Hitch Problems? #1  

koop

Bronze Member
Joined
May 20, 2007
Messages
60
Location
Madison Virginia
Tractor
Case IH 495
I have a 1991 495 4WD with 1068 hours. When off, the hitch will steadily drop until it rests on the ground. The New Holland dealer I purchased the tractor from (with about 1040 hours) swore this was not something to be concerned about. I took him at his word until recently I attached a scraper blade and found the only way to raise it fully was to set the draft as light as possible. The hitch seems to pulse as it tries to keep the implement fully raised. This is my first tractor so I am unsure of what is normal behavior. Any advice would be appreciated. Thanks
 
   / 3 Point Hitch Problems? #2  
It sounds like a cylinder rework is in order. Dealers will say almost anything ambiguous to sell a tractor.

I would approach him about repairing it(since the statement that it wasn't a problem is, in my view, a statement of warranty), but not get my hopes up.

Chris
 
   / 3 Point Hitch Problems? #3  
well lucky you i just bought a mitsubishi and the lift will not go up.i am trying everything that the seller tells me still it does not work.it has fluid and the pump works. fluid is jd20.
 
   / 3 Point Hitch Problems?
  • Thread Starter
#5  
Thank you for all the helpful info.

Does the fact the hitch drops when the tractor is off indicate a leak in the system or do some hydraulic systems just naturally drop when not pressurized?
 
   / 3 Point Hitch Problems? #6  
koop said:
Thank you for all the helpful info.

Does the fact the hitch drops when the tractor is off indicate a leak in the system or do some hydraulic systems just naturally drop when not pressurized?

Yes, It is a leak of some sort, either internal or external. External leaks leave a tell tale sign that you can find a source. If it is internal then by process of elimination you can find a source. If your control spool valve, some relief valve main or lift cylinder leaks then pressure can not be maintained and the lift will drop due to it's weight. Saying all of that it seems 9 out of 10 is the lift cylinder ring/seal (usually Nylon made) that fails. There is a simple affective method than you can almost eliminate that possibility. the test is simple and needs no tear down. almost all 3 pt lift system have a rate of drop needle valve and knob right under the tractor seat. When the spool valve is set to drop the 3 pt lift the trapped hyd oil returns thru this orifice back to the oil reservoir. By adjusting the needle valve in or our you can reduce or increase the rate of how fast the fluid passes the valve. All you need is to lift the cylinder as high as you can and reduce the rate of return to zero, effectively closing the return passage, if the arm drop then you have 99% chance the piston seal is not holding tight. I would do that test before anything else. Good luck.

lift cylinder head, piston and cylinder:



Cylinder head, the hole in the middle has the rate of drop needle valve:



Lift system with rate of drop knob on the cylinder head.

 
   / 3 Point Hitch Problems? #7  
Next time he tells you it isn't a problem ask him to lie on the ground with his neck under the edge of a heavy rear blade to watch it. Then shut the tractor off and see how long he stays there.
 
   / 3 Point Hitch Problems? #8  
When I was growing up with farm tractors, the 3-point would hold for months, even with 2000 lb loads on them. The 3-point on my tc45 nh will hold a tiller for over a week(that is as long as it has been there).

That isn't normal, but is predictable for older tractors, or ones with dirty oil. A little flaw at 2500 psi will leak a significant amount of oil.

The advice listed in the tag above is good:

relief valve leakage
o-ring leakage
control valve contamination
pump(not as likely if your fel works)

Chris
 
   / 3 Point Hitch Problems?
  • Thread Starter
#9  
daTeacha said:
Next time he tells you it isn't a problem ask him to lie on the ground with his neck under the edge of a heavy rear blade to watch it. Then shut the tractor off and see how long he stays there.


Thanks for the laugh, I start my negotiation with Jamie with that!!!
 
 
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