JD955 with no lift at 3pt.

[The Haymaker]

Hi, posting for my Dad. The 3pt has no lift unless rpms are up, then it's very slow. He rebuilt the piston and cleaned any debris he found. Put it back together and it worked better than is has in some time. For a day.... Now it is back to being slow.


Rest of hydraulics seem fine.

Ideas?

E

 

[J_J]

How much pressure can the 3pt lift generate when you raise the lever to max? ?

 

[The Haymaker]

It came up slow at idle, with my 144lbs on it, it stopped until idle was brought up. A steady, solid lift, no mushiness. My thoughts are a sticky relief, but he said he cleaned it.

tomorrow is a bigger test, he's gonna throw the Kuhn on it and see if it will lift it. Roadsides are due!

 

[Johndeere3720]

Could there be any souring on the cylinder wall? This would allow the pressure to escape past the piston. My Yanmar had a similar issue but the 3 point hitch was very weak. Another thing that it could be is the speed valve for the hydraulic lift is loose and needs to be adjusted. hope this helps.

 

[project_X]

It is similar to my thread:
http://www.tractorbynet.com/forums/hydraulics/218240-aaargh-3-pt-hitch-not.html
I haven't torn the control valve apart yet...

 

[The Haymaker]

UPDATE!

So, my dad has run the gamut on this rig, I think he may have lost a little hair over this one. He rebuilt the piston and noticed a SLIGHT improvement. He took a chance and honed the cylinder. There was an improvement, but it did not cure the problem. It did stop the settling of the hitch that has been going on for a few years.

He cleaned the pressure valves and replaced every o-ring he came to in that section of the tractor. He inspected the 3pt control valve. Nothing.

He had the local Deere shop stumped. Their last recommendation was toasted seals on the charge pump.

So, he just replaced a 35.00 chunk of hose on the return from his added spool valves, which is not a new addition. At the same time, he also found that the filter was loose, though not leaking. He had changed it last about a month ago, just prior to this issue, without removing the MMM.

PROBLEM SOLVED. Either the filter or hose was sucking air. The filter leaked no oil until yesterday and the line just stayed wet.

Back when this started, he thought the oil looked frothy. I asked him where he was sucking air and he said there was no place it could happen.

The old man is pretty happy right now, despite wasting a LOT of labor when he could have been finishing roadsides or starting the fall tilling, he had a relatively cheap fix!