Stiff brake, won't brake

[Aqua Angel]

i have replaced my differential yesterday, it wasn't to bad of a job to do it, but i ran into some problems along the way with my rear brakes.

I had to replace my wheel cylinder on the driver side as the bleeder got stuck and snaped. So i had to get another one with all the new goodies with it.
ie new brake lines, new shoes, wheel cyl and spring kit.

my dad and i blead the lines "all 4 of them" for quite some time and occasionaly, i apply the brake "on test drive" it will suddenly become stiff and won't brake. The thing is, it doesn't do all the time. 80% of the time, it will brake on a dime and some odd occasion, it will become stiff and hard to stop.

anybody have an idea of what might be the problem? i am pretty sure there is no air pocket in there, but i thought that maybe my brake booster is going or the master cyl.

or maybe a bad vaccum line?

[Kings-x59]

could be a bad vacuum line. specifically check the vacuum line to the brake booster. A stiff brake pedal is usually an indication that the booster is going bad.
A soft or mushy brake pedal would be air in the system, or the master cylinder going out.

[Aqua Angel]

Cheers, thanks. i sort of knew about it, but i wasn't sure.

my new implant is great. LMAO my new difff i meant. i saved a bit on fuel and i have gain a bit more power and no more weird bouncing noise in the back of the van.

i will replace that brake booster and master cyl though. just to be on the safe side. Still don't know how long i am going to keep the van as my van will be a donor soon for another Astron Van ext with the digi dash this time. WOOOHOOOOO

LMAO