3-Point Hitch Weak hydraulic MF135

[fengen]

Hi folks, I need some brains to pick.
I am working on an old 135, where the hydraulic is acting up.
The pump works just fine, new filter and all is fine and dandy.
If you connect anything to the auxiliary outputs it's all good.
But, and I will try to explain as much and good as I can.
There's barely enough power to the 3-point to lift the bars by them selves.
You can lift it up without issues by hand - so the cylinder isn't stuck.
From what I can deduct, there has to be a valve that let the pressure pass so that the 3-point can't lift.
Could it be a faulty relief valve - or am I far off target?

 

[Agvg]

Any damage or slack in the center link clevis? Particular in and out of the housing?

 

[wagget]

Agvg,
I am having a problem similar to this in that my MF 135 without pressure control would lift all the way to the top and then settle back to the bottom of postion control. I could lower draft control and it would take all pressure off of the lift bars. I then adjusted the adjusting screws that are up against the actuating lever on the pump. with no implement the lifts responded very quickly and seemed to work fine. then I connected a small set of disks to the tractor and upon lifting I heard a metal thunk and the lifts would now only get to the bottom of position control no matter what. removed the implement and the lift bars will lift rather slowly but will get through their full range, however if I attach and implement it will only bring it to the bottom position of the position control. could an issue with the draft spring cause something like what I am describing?