Pedal to floor even after bleeding

I have replaced the rear shoes and cylinders in my 05 Tacoma. After a little encouragment, I was successful in that. Then I bled the brakes starting at RR, then LR, then RF and finally LF. I have watched the reservoir to make sure it is full. This was done with engine off and appeared to be successful until I started it and then had little to no brake. So then I repeated the process several times to no avail. The last attempt was done with engine running.
What am I doing wrong?

 

Are you pumping up the pedal slowly after you bleed it and start or just starting it up and putting the pedal to the floor? Be careful doing that you can overextend things and cause a problem in the master cylinder.

 

Actually, it doesn't exactly go to the floor with engine running. It sort of pumps up a bit but is pretty soft. I am not sure what you mean by "pumping up the pedal slowly after you bleed it and start".

 

Sounds like you have air in the system some how

 

There's an outside chance you've got some air in the ABS controller, which would require it's own special bleed procedure, but that's kind of unlikely IMO. When you were bleeding the wheel cylinders, did you use the two-person method, and if so, how did you do it, or did you use specialized equipment? Why did you bleed the front if you only worked on the back? If you start the engine, wait a second or two, and then press the pedal slowly, what happens?

 

After you bleed the system and start the truck the pedal is going to go almost to the floor the first couple of times you press it. You want to give it multiple short pumps to build up the pressure. If you put it to the floor you can potentially cause a problem in the master cylinder itself. If you have done this and still don’t good pedal then must likely you haven’t got all the air out yet.

 

Are your rear brakes adjusted correctly after replacement? If the adjuster(s) are too far in then you have more travel before the shoes contact the inside of the drum. How does your parking brake feel?

 

I also bled the front thinking I should bleed all 4. I started engine and slowly depress pedal. It goes down about 3/4. I slowly pump it and nothing changes.
As far as brake adjustment, when I turn the drum, I hear a slight scrapping sound. Doesn’t feel too tight. Parking brake feels fine.
I bled the system using the one person method I found on YouTube. It worked fine as I needed to top off reservoir several times. I always did it until I saw no air in the tube I used.

 

I know you were questioned for bleeding all 4 corners but you did the right thing doing what you did. Since you’re bleeding the rears makes total sense to flush out the old fluid on the fronts. If the shoes are adjusted correctly I’d guess you’ve got a pocket of air trapped in the lines. You’ve best bet is to borrow some kind of vacuum bleeder. Try adjusting each wheel until the shoes are hard up against the drum (won’t spin) and then back the adjuster off the specified amount. I don’t know the exact number of turns but somewhere around 5 turns.

 

Nothing wrong with bleeding the front, and concur on the cleaning out of old fluid; I just wanted to ensure that none of the story was missing. I'm guessing that perhaps your one-person method wasn't quite as good as it should have been.

 

Well, I got it handled by using a method I found on YouTube. I hooked up plastic tubing to FL bleeder and ran that directly to the fluid reservoir and pumped brake like hell. It turns out that I had air in the master cylinder that was causing all the problem. Great fix!