2004 Avalanche brake problems?? need help!

i gotta 2004 Avalanche and i just changed the front brakes. Its disc brakes all 4 tires. I had took the break lines off the calipers in the front, replaced the pads on both sides, blead the lines on all four tires starting from the farthest rear point to the closest front point to the master cylinder and all the air seems to be gone. But when i turn over the ignition and pump the break pedal it goes right to the floor with very little resistance and the service brake system message comes up on the odometer....anyone know why its doing this??

Did the master cylinder suck air while you were bleeding the system?? If you bled all four wheels its possible to run out of fluid in the master cylinder. Did you replace the front brake lines?? If you only removed the front line or both front lines you only have to bleed the front not the whole vehicle. If you allowed air to get into the master cylinder you may have air trapped in the ABS modulator which requires a specfic bleed procedure that requires the Tech II the open and close each valve inside of it.

I just replaced the front brakes but i had to unbolt the brake lines from the caliper because i couldnt break the star heads loose that hold the caliper to a bracket. I had to take the whole bracket and caliper off to be able to get enough leverage to break the star heads loose. I didnt replace any brake lines. I blead all four lines because i didnt know if i had somehow gotten air into them when the trucks front end was jacked up and i took the brake resevuare cap off to fill with fluid. I never let the fluid run completely out of the master cyclinder.

When you put it all back together did you notice if the brake lines are leaking after you bled the system. there is a copper washer that goes between the brake hose and the caliper. Did you tighten the bleeder, maybe there is a small leak.

If you dont see any leaks whatsoever you may need to take it to a local repair shop and have them pressure bleed the system.