Leak from brake line fitting at distribution block

[MiamiMJ]

I could use some help.

 

I did the WJ brake booster upgrade, but I had a leak at the back of the distribution block. Fluid was coming up out of the top of the rear fitting. Pulled everything out again, took a new set of lines to my mechanic--thinking maybe my lack of experience in making double flares was the problem--and put everything back in.

 

Today I went out to bleed the brakes and finish the job when I noticed that fluid was already coming out of the rear fitting again, without ever having depressed the brake pedal. The line is new again and the brake line fitting is new again. Could it be my distribution block (or is it called a front proportioning valve)? If something is gummed up, can I fix it so the double flare seats right again? Or do I need to find a replacement block? Maybe there some other answer?

 

Appreciate everyone on this site. It's been a huge help.