Lift question on 640

   / Lift question on 640 #1  

Loadstar

Platinum Member
Joined
Mar 16, 2012
Messages
791
Location
Evansville, IN
Tractor
Ford 640
Most of the time I use a hydraulic cylinder for my top link. Just about all my implements work with that. Three implements I use hook directly to the top link on the tractor(boom, cement mixer, post hole digger). We rebuilt the lift a couple of years back and it has been working great. Hydraulics are strong and can lift tractor, arms raise and lower fine and do not really bleed off. The main focus of the lift rebuild was the arms were not raising all the way up (dowel was worn in half).
Here is the issue I have a question about. When I use the post hole digger the lift seems to have a mind of it's own. About all I get is full up or full down. This is a puzzler to me because this is the only thing it does this with. If I put it in the middle it bounces the auger like a pogo stick. It stinks because it's hard to clean auger. Once I'm done digging I raise the auger have a split second to spin it before the u joints are at too poor of an angle to spin PTO. Having my hands on this things guts before and teaching myself how it works I really can't think of a reason for this. By the way I am not expert, I am just a hands on guy that reads manuals (maybe that's why this is a puzzler)
 
   / Lift question on 640 #2  
augers need low rpms.

at low rpms.. your hyds are going to be very low volume, slow to respond, and any leaks int he system will gobble up flow quickly.

ie.. at high rpm, you can make 4gpm,.. say you have a 1gpm leak.. no biggie.

now say you are at 1/3 rpm where you should be for augering... your flow is now JUST above the leak rate.. menaig you have sluggish, slow hyds that may work eratically due to the backpressure valve and unloader valve working under those conditions.

also make sure you are not in draft hyds mode.. and make sure the auger is not binding at the toplink rocker making it change lift geometry
 
   / Lift question on 640
  • Thread Starter
#3  
Always to my rescue and I really appreciate it.

Here is the thing I should have mentioned: it does this with the PTO off and rpms do not seem to effect it. It really confuses me.
I have only wittnessed this with the auger. Where it hooks on the top link is wider than any other implement. I was suspecting a binding issue but my attention is always diverted to the drill site, bystanders, and surroundings. When I'm back there making sure everything is working ok it sways ok side to side like nothing is bound. If I have time I will take a picture of it hooked up.
 
   / Lift question on 640
  • Thread Starter
#4  
By leaking do you mean internally? Can you elaborate a bit so I'm on the same page with you?
 
   / Lift question on 640 #5  
yep.. internal leak offs.

on many augers.. they have funny legerage / toplink setups unlike a regualr mower of box blade. it can amplify their movements at the end due to the lift geometry.

enigne speed directly effects hyds speed on that tractor.

rated engine speed needs to be achieved to get rated hyd flow.

it's proportional down the line..
 
   / Lift question on 640
  • Thread Starter
#6  
I just don't get the no in-between or pogo auger. If I lift it it's gotta be all the way up.
 
   / Lift question on 640 #7  
disconnect the toplink and see what it does..
 
 
Top