I changed my brake pads yesterday. We were having a problem getting one of the front pistons to push back in so opened the bleeder and pushed it back in. Because it was so easy to do this way we decided to just do it for all of them. My friend was working on one of the front calipers and i had started working on one of the back. Well me not thinking had taken the rear caliper off and the pads out, then my friend was ready to bleed the front brakes. I got in pushed on the pedal and one of the rear pistons came all the way out.

I took the caliper off, emptied the brake fluid, I put the rubber/metal ring back on the piston, pushed the piston back in, and tried to push the metal part of the ring back in the caliper. My question is, did I put it back together properly? It seems like it's still leaking but it may be just me being paranoid.

Any ideas?

And sorry for not searching, I couldnt get the search tool to work.