[AT] JD 4020 lift problems

[Cecil Bearden]

John:
JD 4010 &4020 have a screwball type of depth control.  The shaft that 
connects the lower links goes through the rear end case and bends when 
it gets loaded.  The amount it bends causes the draft control to raise 
the lift. Sounds like your boom lift is causing the depth control to 
work backwards. I think a selection on the small lever under the front 
of the seat will take care of some of that.

Cecil in oKla

John Hall wrote:
> When we try to lift something really heavy with the 3pt hitch with dad's 
> 4020, it has become a struggle lately. You have to rev up the engine a bit 
> and then it will start letting it back down instead of holding it. I don't 
> suspect the pump since we have no trouble lifting equipment with cylinders 
> on it. We really notice it when we have the boom on it. So you can 
> understand, this boom is made out of the tongue of a log cart, to put it in 
> size perspective. We always knew when we were lifting too much as the 
> tractor would lift it's front end off the ground.
> 
> Anyway, does this sound like a valve with an issue or possibly bad rings on 
> the lift cylinder? Maybe something with the load and depth control?
> 
> John Hall 
> 
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