Hydraulic brake actuator issues-Missing cable?

[Serf27]

Hi,

I have a hydraulic brake actuator on my boat trailer.
I have read on how they work and what a lever on the trailer is used for.

The lever on top is to release the brakes when I am backing up, correct?

I am missing the safety cable to triggers the brakes if the trailer is to detach from the truck.
Does anyone know where I attach the safety cable?

The system is not working right now because I can back up the trailer without touching the release lever.
I need to add some fluid and try to bleed the air out.

I do not see anyway to bleed the air out like other trailers that I’ve seen online.
Does anyone know how to bleed the air out?

And how Do I secure the coupler to the hitch/ball?
It has the top lid/flap that I flip down when I drop the trailer on the hitch and I just keep the flap down with a wire attached to a “d ring” type piece.
I just noticed yesterday there is 2 small holes on the coupler where it looks like a pin slides through…?
I’ve attached photos.
Thanks.

 

[alldodge]

Never seen one like that and would be guessing. My guess is the piece that comes down to keep the latch closed also applies the break if it comes loose.

If it was mine, I would get rid of it and install a more modern one