brakes go to floor

[K10-Kansas]

EDIT: SOlution found. I had my calipers on with the bleeder screw pointing down instead of up.

EDIT: Update: I replaced the master cylinder brake lines because I felt that they weren't getting a good seal. They were 51 years old. Bench testing the master cylinder shows it working well. I adjusted the back drums and they are so far out now that it is really tough to get the drums on and off. I put the bleeder bolt in the proportioning valve. Bled all of the lines again. I added fluid to the master cylinder everytime it got down halfway. That happened about times. And the brakes still go to the floor. I can build up a little bit of pressure if I pump the brakes several times but even doing that, it doesn't stop the wheels from spinning. I've got it up on stands with the tires off.

Any suggestions?


Hello all. I hope you can point me towards things to check. My truck is a 71 c10 cab and what I am guessing is a 77 or 78 K10 chassis. I've owned it for a year working on it had have driven it for a whopping 2 minutes in since I bought it -onto a trailer and then off a trailer.

I had it up on blocks working out some confusion with the transmission. I started the truck and put it in drive and pushed on the brakes and saw that the wheels were still spinning so I push them to the floor and then the right front brake line burst. I replaced the brake line, bled the brakes, and they still went to the floor. I pulled off the drums, adjusted the brakes, bled them all again and still going to the floor and not stopping the rotors and drums from spinning. The booster is brand new put on there 5 months ago and seemed to work fine for the whole 2 minutes I pulled it off the trailer, parked it, moved it a few times 20 feet.

If I push the pedal in and out 3 times it builds pressure and then doesn't go to the floor but if I wait a few seconds and push it in again it goes to the floor.