Well I replaced my master cylinder
Bled brakes as best I could (they were still spongy but still worked)
Then the booster quit working (well it was barely working if as all)
I drove the truck about 3 weeks then yesterday on the way home the brakes went out
Each time I pushed the pedal down it went down a little further until nothing.
So I checked the fluid and it was very low but I can't find a leak, I fill it will fluid and try to bleed them to no avail.
Any ideas

 

the master cylinder is filling up booster ..