When we fitted our loader on our
Ursus C-385 A first, we had a similar problem with the hitch.
Then we figured out that the system had two return lines, one for
oil overflow when no pressure is needed and the oil flows back to the reservoir and one pressureless return for oil that returns from the cylinder when you move it up or down.
The oil from the first mentioned line should flow through the hitch valve block too.
My neighbor, and on our own loader, we use one line from the external hydraulics at the back to feed the loader, so we never get trouble. However plumbing the loader directly to the pressure line before the other valve blocks would be a nicer solution, you keep your external remote free for other uses.
So, you cant make a split off of the oil lines, they have to be plumbed in series, not parallel.
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Hey, eh... like Crystalman said it....