hard brake pedal

Just put front discs on my 64 grand prix along with a dual chamber master cyl. I kept the stock power brake booster. Now the pedal is hard as a rock, but it doesn`t want to stop. This set up should put you through the windshield!

 

what master did you use? what brake pads?

 

Make sure vacuum is good at the booster and the booster is working correctly -

With the engine off pump the brake pedal a bunch (10 or so ) of times. Then with your foot pressing on the brake pedal start the engine. You should feel the pedal depress under your foot when the vacuum gets to the booster.

 

What size front calipers and what size MC did you use? If the MC is too big the pedal will be short and hard. Are you sure the booster is still working?
With the car off press the brake pedal to bleed out any assist. Keep your foot on the brake pedal and start the car. Does the pedal drop or stay in the same spot?

 

Thanks to all who replied to my question. The car is in the spray booth ready for paint, when it comes out Im going to replace the booster. The probable cause to the hard pedal. Thanks again all. I will be posting pictures when its done!