on the 82 f150 We got this same problem after a new MC... This was after replacing seised calipers, rusted hard lines, squishy ruberlines and bad wheel cylinders... (put away wet/muddy many a time)
After giving up, we took one of the wifes vehicals to the cabin for the weekend. When we came back, the frount brakes were better and we had good pedal feel...
We just couldnt get the backs to bleed, which ended up being a proportioning valve (ugg)

After all the new parts, we had a stubborn air pocket somewhere, and letting it sit helped...

If you need this everyday, I'd call a few shops and see if they have a powerbleeder, and what they charge to use it... If not, let it sit for a day or so, and try again.


Or you could have a bad booster, but I really dont know

~Nate

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95 Honda Shadow ACE 1100.
1999 Plymouth Neon Expresso. 2.4 swap, 10.5 to 1 comp, big cams. Autocross time attack vehicle!
2012 Escape, 'hunter" (5 sp 4cyl)