International B250 hydraulic problem

[Jeepfan]

Hi all. I have an old (1957) Inter B250. It functions relatively well, but the 3-points hydraulic doesn't hold. It lifts no problem, but simply doesn't hold, and gets all the way down within à few seconds. It has enough hydraulic fluid, so that is not the issue.
Any clue of what could be worn/broken, and repair tips ?
Grreetings from Quebec, Canada

 

[mengeleguru]

Your main lift seals on the piston are probably leaking.
With weight on do the lift arms hiccup, while it’s running.

If so it’s the seals.
Could also be the lowering control valve not seating, but unlikely

 

[Oliveau]

Hi all. I have an old (1957) Inter B250. It functions relatively well, but the 3-points hydraulic doesn't hold. It lifts no problem, but simply doesn't hold, and gets all the way down within à few seconds. It has enough hydraulic fluid, so that is not the issue.
Any clue of what could be worn/broken, and repair tips ?
Grreetings from Quebec, Canada

Seal on the piston inside the top cover