640 Ford vane hydraulic pump prime

[Russell Moore]

How do I prime the vane hydraulic pump on a 640 ford tractor
Thanks for any help

 

[Andy Wickiser]

Here is a courtesy except from the I&T.

<IMG SRC=https://i.postimg.cc/7Zrhdg97/Ford-Vane-Prime1.jpg>

 

[Russell Moore]

Looks like my pump is no good
Will the piston pump off a later model 600-800 fit directly onto my 640

 

[Sean in PA]

You will need a different manifold to go between the pump and the front corner of the transmission, but other than that it will bolt right up.

 

[Andy Wickiser]

Yes the piston pump will work but you
would also need to change the manifold
assembly.


One thing not mentioned is failure to
prime/failure to hold prime can also be
caused by an air leak on the suction side.

 

[Russell Moore]

The piston pump came off a 801 and I finally got it bolted up using the manifold that came off the 801 just like you guys said
Now I have flow at the prime screw on the pump but my lift still will not raise

When I bought this tractor the lift cap was off because the previous owner had torn the ring and pinion gear out of it
He did say the loft was working when he last used it but we all know how that goes

 

[Sean in PA]

The piston pump came off a 801 and I finally got it bolted up using the manifold that came off the 801 just like you guys said
Now I have flow at the prime screw on the pump

The piston pump does not have a bleed/prime screw. Only the earlier vane pump has that. To bleed the air out of the system and prime the pump with a piston pump, You need to loosen the test port plug on the blocking plate, which is the large hex head plug on the 3x5 plate that you see when sitting on the tractor seat and look straight down between your knees. Loosen that plug, but don't remove it completely, then start the tractor and wait until only fluid is coming out around the plug with no air bubbles, and then tighten the plug back down. If no fluid comes out around the plug at all, use an air hose on the fill hole to add pressure to the sump until fluid starts to come out around the plug.

 

[Russell Moore]

I got it figured out
Someone had removed the pump relief valve in the bottom of the lift cap housing

With that removed once I got the pump primed fluid was just going right out into the sump
Once I installed that valve the lift works like it should now
Thanks to everyone for the help