Trolley jacks

[PaulXR50]

So the other week i bought a Toolpro low profile trolley jack 3000kg.

Wondering if anyone has one of these and can tell me something about ‘purging the air out of them and when to know the valve is completly closed.

I have followed the instructions about keeping the jack low and pumping handle a few times and same when fully raised.

Under a cover plate seems to be a large alan key screw, anyone know what size this is ? Is larger than any key i have.

From what i have read this needs to be unscrewed a little to get any remaining air out.

The other issue i have is when the handle is inserted in the jack (handle kept flat) to close the valve to raise it, the handle just keeps turning but every few turns you can feel a ‘notch’ (would be best way to describe it) its then you can raise the jack.

Is this normal or is there a point when the handle should come to a stop so know when valve is completly closed?

Thanks in advance.