Brakes

That happens to all of us. Just shove it back together and rebleed it.

Well, actually, don't just SHOVE it back together. Nothing serious has happened yet. There is a lip seal that must be pushed in sideways to prevent catching the edge and ripping it, but from your pictures it hasn't come out yet. It is on the inside of the piston which is what you're seeing. A spring inside is pushing the two pistons apart so those two lip seals don't fall over. That spring is what pushed the piston out. The dust boot holds them back in.

The shoes hold the pistons in too. If you were pedal-bleeding, the pressurized break fluid is what pushed the shoe and piston out if the drum was off. Still, no harm done. If no brake fluid ran out, the lip seal isn't out far enough to cause a worry. That's what it appears in the pictures. Just push the piston back in and pop the dust boot back in place. This is less likely to happen with an old wheel cylinder because rust forms on it that "glues" the dust boot in place.

If you're pedal-bleeding with a helper you have to leave both drums on, otherwise the pistons will come out. That's what they're supposed to do but they're stopped by the drums. I only gravity-bleed. There's no pressure in the system then so the drums don't have to be on. The return springs on the shoes will hold the pistons in.

I should make you aware the site is having a problem with your posts. I think this is the third one I've seen about this car and problem and every one is acting the same. We get one chance to post a reply, then when the page refreshes, it goes to a Bronco problem from 2006. Even the links in the automated e-mails we get switch over to that Bronco. Once I post this sad reply, I won't be able to get back here unless you post another followup question or comment. Don't know why this is happening but I sent a message to the site owners about it already. Just want you to understand why I might not reply. If I don't, and you need me, copy and paste your comment and click on my user name to send me a direct e-mail message.

Okay, this time it worked normally. Go figure. Maybe they fixed something or maybe the computer just got over its tantrum.

Carry on.