600 Hydraulic problem

[mike wallace]

I recently purchased a 640 ford that had been sitting for about 1 1/2 years. I have it running, but the lift doesen"t work. I have checked the fluid and the level is OK, color is yellowish. I thought it may have lost prime, I tried removing the allen plug in the pump with the tractor running, I didn't take the plug out because there is pressure at the allen. Pressure was enough to spray, I'm not sure if it is what it should be, but I think it should be enough to get some movement. Any suggestions?

 

[souNdguy]

Betcha something in the unloading valve is froze or gunked up..

soundguy

 

[Dave from Texas]

I just went through that with a 841 that had been sitting for 5 years. My control valve was stuck. Cost me about $15 to renew the gaskets and "O" rings. Not a hard job but the cover is heavy. Mine works great now.

 

[Anonymous-0]

I would also drain and refill the rear end as it has been sitting so long. Will get rid oif any crud and water that may have accumulated in there. Also, would recommend blowing some air back through the supply line from the pump to make sure there is no sludge blocking fluid coming to the pump.

 

[mike wallace]

MB
I will change the fluid after I blow the lines out. Can you suggest the best way to get air through those pipes, do I just remove the pump and blow air through it with a compressor or is there a better way?
Thanks,
Mike

 

[mike wallace]

It was suggested that I change the fluid and blow the lines out. I want to be sure I get this problem fixed. Can you tell me how to complete the work you suggested?
Thanks,
Mike

 

[mike wallace]

Hi Soundguy,
I have received a couple of other responses. They also speak of gunked parts. Can you suggest how to get the valve you mentioned working?
Thanks,
Mike

 

[souNdguy]

If you are the real lucky sort.. sometimes a drain, flush and refill of hyd fluid will work the debri loose..

If not.. you will actually have to tear into it and take a looksie.

I suggest having -AT LEAST- the I&T fo-20 manual, if not the ford shop manual on hand for this type of repair.

soundguy

 

[MB]

To blow the lines out, you would need to take the lines loose from the bottom of the pump. The lines are in a cast piece that runs from the front of the transmission to the bottom side of the pump. Once off you should have two internal lines going from the front of the transmission back to the rear end. One is the feed and the other is the pressure line. Blow air through the feed line to make sure it is clear. My brother's tractor quit working and this was all it needed. The drain port for the rear is on the bottom of the rearend.

 

[mike wallace]

Thanks