70 Challenger brake issues

[Wyo70Mopar]

Hey guys I have a 70 Challenger with power brakes, disc on the front drums on the back. The front brakes have been gone through and when I bleed the brakes I get good fluid on all the brakes but it feels like it has manual brakes. I have to push really hard on the brakes to get the car to stop. Do you think I should change out the brake booster?

 

[quapman]

Was the car front disc originally? If it was a disc conversion, did you change the proportioning valve? Disc/drum uses a different one than drum/drum.

 

[Wyo70Mopar]

The car has always had the disc on the front since we owned it and it looked original but it wasn't originally power brakes would that make a difference?

 

[704406]

First check that the engine vacuum is getting to the booster. Then check the booster operation by pumping the brakes with the engine off, get the brake pedal hard, while holding pressure on the brakes, start the engine. The brake pedal should go towards the floor a bit.
defiantly check the proportioning valve as Quapman said.
manual brakes and power assist brakes take different master cylinders.
Have the brakes ever worked properly since you've owned it?

 

[Adam]

It could make a difference if the swap used the wrong master cylinder; e.g. too big of a piston. More than likely the booster is getting insufficient vacuum, or is leaking vacuum, as 704406 said above.

If you need your original booster rebuilt “Booster Dewey” does great work at a reasonable price.

 

[340challconvert]

In 1970 Challengers, if you ordered disc brakes, you had to have power brakes. If your car had factory disc, you had the factory booster.