[F30berk]

I have a 2003 s10 4x4 crew cab with abs. I was having issues with the brakes when I purchased the truck a few months ago. I replaced all 4 calipers, rotors, pads, and wheel speed sensors. When I went to bleed the brakes, I noticed the line rotted and was dumping brake fluid all over the driveway. Overnight the entire system was drained dry because I wasn’t able to get the brake line until the next day.
I bled the calipers and I get a firm pedal with the truck off, but the pedal goes straight to the floor with the truck running no matter how many times I pump it. What am I missing here??

 

[1985BlazerS10]

I don't have a solution, but don't all the guides to servicing brakes warn never to let your whole system run dry during bleeding because you'll then need to bleed the master cylinder separately prior to bleeding the rest of the system?

Could that have something to do with it?

 

[F30berk]

I don't have a solution, but don't all the guides to servicing brakes warn never to let your whole system run dry during bleeding because you'll then need to bleed the master cylinder separately prior to bleeding the rest of the system?

Could that have something to do with it?

Definitely. It only got run dry because one of the lines rotted through at night. I couldn’t get the brake line until the following morning to repair it. Gravity did the rest

 

[oldeerslayer]

Having done this numerous times, first be absolutely sure you don't still have another leak. Sometimes repairing one section cause movement in the next piece and it starts to leak.
You can bench bleed the master in place. Just need to take the 2 lines off and run hoses back into the reservoir.
On a CC, with it's miles of brake lines, pressure bleeding is the best way to get all the air out. Even then I'd start with at least 2 quarts of fluid.

 

[F30berk]

Having done this numerous times, first be absolutely sure you don't still have another leak. Sometimes repairing one section cause movement in the next piece and it starts to leak.
You can bench bleed the master in place. Just need to take the 2 lines off and run hoses back into the reservoir.
On a CC, with it's miles of brake lines, pressure bleeding is the best way to get all the air out. Even then I'd start with at least 2 quarts of fluid.

Thanks. I’m positive I don’t have another leak. I bled the master and rebled all the lines at the calipers. I still have a very firm pedal with the truck off, but with the truck running the pedal goes to the floor. Once I turn the truck off again, pedal is firm again after 1 or 2 pumps

 

[PawPawBallas]

Don't know if you fixed it, but it sounds like a vacuum problem. Check the brake booster.

Thanks. I’m positive I don’t have another leak. I bled the master and rebled all the lines at the calipers. I still have a very firm pedal with the truck off, but with the truck running the pedal goes to the floor. Once I turn the truck off again, pedal is firm again after 1 or 2 pumps