[joshbarnett]

Do they work better on a 2nd pump on the pedal while trying to stop the car?
Reason why i ask is because this would indicate air in the lines, (usually the back) and bleeding the whole system would help.
Also, is it disc or drum in the rear? If drum, they could probably use adjusting and this will increase your stopping power greatly.

It's disk brakes all around. Also, the brakes actually work better on the first pump after driving without braking for a while. After that first pump, they get pretty weak. I wonder if this has something to do with the vacuum booster. The motor has a very aggressive cam in it and the vacuum at idle is literally like negative 6 psi. So it probably takes a little while to build up the vacuum in the booster, but once you brake, it doesn't replenish very quickly and if I'm braking again and again in close succession, the brakes just don't work very well. Maybe I should get a vacuum canister. But then again, even with weak vacuum the brakes should still work fine just with a little more work by the foot. Really not sure what's doing on.

 

[joshbarnett]

Check this out....adding a vacuum booster..

Adding Vacuum Assist for Power Brakes - 49FordCoupe

The vacuum reading of the engine is about 12.5" Hg, and my power brakes were a little scary. So, here's how I fixed it.

49fordcoupe.smugmug.com

Great info. Boy that guy's idle vacuum is 12.5. Mine is more like 7.5. No wonder it's so hard to stop the car.

I don't have the exact specs for the cam inside other than it's "very big", but is it even possible that a cam is so big it creates such low vacuum? What do you guys with aggressive engine configs see vacuum-wise usually?