Brake Problems

[LEWETHETIGER73]

So here is the story. I have a 1973 Pontiac LeMans that had a 350 2brl. I recently changed it to a 455 with a 4brl and edelbrock intake. Since then my brakes got weaker and then gone. I have checked all the lines and brakes and they are fine, I think there is a small leak in the rear seal but that can't be the only issue. I started the car today to see how the pedal was and with it in park it went right to the floor board. I tried pumping the brakes to see if I could force a leak to show it's self and nothing happened. No firmness of the pedal at all. Any ideas would be appreciated. Thanks

[Ricky Bobby]

is there fluid in the master, did u suck a bunch of air in lines if out of fluid, if your sucking in air it can cause a spongy pedal

[TheRX7Project]

A small leak won't cause that. The Belvedere has a small leak in one of the rear cyls and I only have to fill the master once every couple weeks or so. Fill the master and bleed your brakes. This will show you where your real problem is.

[LEWETHETIGER73]

There is still fluid in the reservoir. I'll try bleeding my brakes somemore. I was concerened if I am not getting the same amount of vacuum from the motor to operate the brakes.

[TheRX7Project]

Maybe too much vacuum? If you weren't getting enough vacuum you would have a very firm pedal. How does the pedal feel when the car is not running?

If you pump the brakes with the car off, and the pedal gets firm, it's a vacuum/booster issue. If it stays soft with the car not running it's a brake problem.

[whistlin six]

sounds like a bad master cylinder