Best way to block push in air fitting

Up behind my dash, I have an unused 1/4 air fitting port, is leaking pretty bad, its apart of something bigger with 4 - 5 air lines going into it.

It has a little 1/4 air block in it, I put a new 1/4 blocker in there, but it still leaks.

When I get a chance I will try with some hose but I doubt it will work.

Is there a way to block off this fitting, I was thinking some JB weld or steel cement.

Would really like to not have to pull the whole dash out just to get this replaced.

I know its dodge and everyone will say, do the job properly, bit in this instance I think bodgy is worth a try

Thanks

 

I have never done that before, I am assuming I melt the line first and then jam it in?

 

Nah, its not an exhuast, 100% its an unused port, thats just got a blocker in it.