C6 cp auto.
The brake pedal goes almost to the floor under hard braking. I have new master cylinder, new pads front and rear, and rotors were turned.
would appreciate any suggestions.

 

Bleed the fluid with all the brake work?

 

Sounds like air in the system. A good bleeding may be needed.

 

Before doing anything else, check all your connections in the brake system to make sure something isn't loose sucking in air. IE: Hard lines that run to the rubber caliper lines, rubber caliper lines where they bolt to the caliper, make sure all the lines are snug on the ABS block (a 1/2" wrench is what you need IIRC), etc. Also check the vacuum hose coming off the booster to make sure it's secure and not leaking. If you've suddenly experienced a high idle when this problem began, it could be a vacuum issue with the booster.

If all that checks out, find a shop that can do a force bleed for you with a scanner. You don't necessarily have to go to a dealer for this as all of the newer Snap-on scanners can do this as well. Any reputable shop in your area should have the software to do it. The Snap-on Motus and Snap-on Verus can perform this procedure and these are not dealer exclusive scanners.

If there's a bubble in the ABS block you'll likely never get it out bleeding it the old school way. This frustration alone forced me to drop a boat load of money on a good scanner that can bleed the system for me. I got sick of bleeding gallons through brake systems when I can sit back and punch a few buttons on a scanner and let it do it for me while somebody runs around and operates the bleeders.

 

Thanks for the info but the fluids were all changed and system flushed. I will try checking all the connections and maybe the vacuum booster check valve.
Thanks again