new brake booster/master problem

[Big Slim]

I installed a new booster and master combination and its not braking very well. It seems to have a firm pedal but comes no where close to being able to lock up. just a slow stop. ive bleed the brakes several times with no air bubbles coming out. ive adjusted the drums in the back and have disks up front. the only thought i had was the pads are bad. any ideas?

 

[Jonboy69]

what master cylinder is that out of ? Do you know the bore diamater ? It might not be big enough to push enough fluid ? I would go for a 1" to 1 1/4". I have one off of a f250 camper special & I think the bore diamater of the cylinder is about 1 1/8 & it is good.

 

[DirtDonk]

Was it working fine before the swap? If so, it's not likely to be pads. More likely a mis-matched master or an inefective booster. You getting a good vacuum signal to the diaphragms?
When you turn the engine on with your foot on the pedal do you feel the drop? When you turn the engine off and press the pedal a couple of times, does the feel change?

Paul

 

[Big Slim]

it is a tuff stuff master with 1" bore and a dual 7" booster. thats the master that they recomended for disk/drum setup. it is getting vacume. its deffinitly easier to press with the engine on.

 

[broncnaz]

If it wasnt locking up before the swap theres really no reason for it to lock up after the swap as the MC has the same bore size as stock so nothing has really changed except now the pedal is easier to push because of the booster. The booster only makes the pedal easier to push it doesnt make the brakes work better.