I have an 85 4runner that I swapped a 3.4 into. t sat for long time and im getting it going again. I've recently replaced the calipers with the bigger 3.0 ones and the rear wheel cylinders were replaced not long ago. It has a hard high brake peddle but damn near 0 stopping power. I pulled a used booster off of a 94 I have laying around and swapped it out and also got a new master cylinder for a 94. I put it all together and bled the brakes. Everything seemed normal. I went to drive it and it's the same. high hard peddle. no stopping power. There seems to be good vacuum going to the booster. When I pump up the brakes and fire it up the peddle doesn't go down any. What do you guys think I need to look into?

 

Still sounds like a bad booster to me. You said it is getting a good vacuum to the booster, but where from?? there should only be 1 large port for the booster off the intake manifold. With the engine running, pull the vac hose off, it should almost kill the engine. You could post up a pic of the source and set up

 

it has enough vacuum it sucks my finger up. the weird thing is when i pull the hose off it doesn't change the idle any. im also fighting a rough idle on occasion and a loss of power. its been so long since i built it i forget ˟˟˟˟ i did lol. ill take picks of the rig in the am. but it ran well for 3 years after i did the swap. im kind of at a loss.