I just got done with a full rebuild on my 2000 FRC. Brakes were ok before I took it apart. Installed a new LS6 engine with a Texas Speed 228R Cam 112 LSA. Took the car out for a test ride last sat for about 6 miles and it was throwing a C1247 code and the brake pedal was very inconsistent. I had brakes all the time, but sometimes I wouldn't get pedal pressure until it hit the floor, and other times I would have it right away. Pumping up the pedal would bring the brakes back, but any amount of time off the brakes and I'd lose the pedal. Code will clear using the DIC and will stay away if I keep pumping the brakes, but any amount of time off the brakes and I lose the pedal and the code comes back. After the test drive I found the front left caliper locked up solid, and after taking it apart ended up replacing it with a new one. Just started the car on the lift, and still have the same problem. I pressure bled the system multiple times, no air is in the line. With the engine off I have a very solid, consistent pedal, but as soon as I fire it up the problem starts. I'm thinking it has something to do with the brake booster, and a buddy is telling me the cam could be causing vacuum issues. Any input is really appreciated, I've had a host of problems since getting this car back together, and this is the last gremlin and I really want to be on track next weekend!


during the test ride I got it into the ABS many times trying to get the whole system working, with no positive outcome. I've checked the whole system for leaks, and can't see any vacuum leaks. If I pull the differential plug on the portioning block the code will not come back, but still have the inconsistent pedal.

Thanks!

 

Bump I'm desperate

 

Not home now but did a Google search on :C5 corvette c1247. Got a lot of hits like:

http://forums.corvetteforum.com/c5-g...activated.html

Check out what you see and get back to us.