Hard pedal

[dbackse350]

I have a 69 Camaro with 13" dual piston Baer's in the front and 13" single piston Baer's in the rear. Last year I switched to a :headbang:7" dual diaphragm booster and master. I also added a vacuum pump as the engine has a 230 duration/ 510 lift hydraulic cam. I switched from a Delco-Moraine 11" booster only for dress up purposes. The brakes worked great with the stock 11" booster and master. Now, I can not lock the brakes up. And the pedal feels like I have stock manual drums, i.e. hard. I have bench bled the master, bled the lines sevreral times and checked the booster for vacuum pressure. The 7" booster and master were purchased new from SSBC. Any ideas?

[Apogee]

What is the bore size on the master cylinder? Odds are, that's your problem combined with the undersized booster, even with the aux vacuum pump. If SSBC provided a 1.125" bore unit, your pedal would be rock hard and very high, but slow down like a "rock" on a ice curling rink. Given the C4 PBR calipers you're running, you should have something more in the range of a 7/8 to 15/16 inch bore MC IMHO.

The other item you can play with to increase your brake torque is your pad coefficient of friction, however since you weren't having issues before the "updrade", they should be fine as they are once you address the other issues.

Tobin
KORE3

[dbackse350]

Thanks Tobin. I was wondering if this could be the problem. I will give it a shot.

Bobby

[MCB Matt]

We always issue 1 1/8 master with 9" and 11" boosters. Anything smaller needs a smaller bore master....

For what its worth the 7" dual boosters are almost worthless....

Perhaps going manual or hydraboost? The vacuum pumps will not keep up in city driving typically either, no matter what size booster!

Matt