Any ideas why my brakes are not better??

[crazyfireman]

I upgraded from stock drum-non power brakes to the LS1 fronts with cross drilled slotted 13" rotors, all new stainless steel brake lines, and this master cylinder with the vacuum for power brakes. I have a adjustable proportioning valve for the rear brakes also. With all this done my car now stops worse than it did with stock drum brakes. Any ideas?? I have asked the guy I purchased the master cylinder from the bore size so I can see if that is it. It has plenty of vacuum, and acts like the first half of the pedal is assisted but when it starts to apply brakes it is extremly hard to stop.

[bigvegan]

What brake pads are you using?

[Skip Fix]

Have you allowed the pads to seat/"bed" in? Especially teh harder "performance" pads take awhile to do that and have bad perfromance until then.

[crazyfireman]

I havent thought of that. I only have 20 miles on them, I bought the better pads from NAPA. I sure expected a huge difference, not a decline..

[Skip Fix]

Years ago when I put semi metallics on my TA the first stops were scarey!

[whytry]

I have read and heard good things about the HAWK pads..... maybe for future ref...

[David Pozzi]

You need to use a 15/16" bore master cyl with those calipers. Late model brakes use much smaller caliper bores and need more pressure than the old style.
David

[crazyfireman]

Ok, so more pressure opposed to more volume. I am still waiting to hear from the person I bought the master cylinder from to determine the bore I currently have.

[Steve68]

Take it off and measure?

[crazyfireman]

Ok I have a 1" bore and almost no pressure at the cylinders with all new parts, and the master cylinder bench bled. what gives????