Piston came out of caliper

Hey all, I was changing my brake pads and rotors this morning, and I did something stupid. I puished the pads in on one side without holding the others, and the force pushed the opposite piston most of the way out of the caliper. A small amount of brake fluid came with it. I was able to get the piston seated and pushed back in, and the leaking stopped.

I finished changing the rotors and pads, and drove (very carefully) around the neighborhood. It seems to be stopping fine, but the pedal feels squishy. I know I'm most likely in for a bleed, but is there any danger if the piston comes mostly out before pushing back in?

 

Back in the days when some of us used to rebuild our own calipers, removing the piston was part of the program. As long as you didn't get any dirt in behind the piston and didn't damage the square O-ring in the caliper bore, you should be just fine. As you mentioned though, you will need to bleed the air out of the system.

 

^^^^^^THIS^^^^^^

 

@Too Stroked Thanks! I'll do a bleed and keep an eye on it. As long as there's no leak I should be good to go on the dirt and square o-ring, right?

 

Make sure you seated that outer dust seal.
Here are some pics of what the outer looks like and the inner o-ring in the bore:
2 Gen Caliper Rebuild | Tacoma World
If you did not spray the caliper with brake cleaner before you pushed the pistons back in and one came out dirt may cause sticking issues.

 

That's probably the best thing you can do right now since it's all back together. Dirt behind the seal can cause wear of either the piston surface or the square O-ring leading to eventual leaking of brake fluid. As you might guess, that's not good.

As for bleeding the system, you're most likely in luck since most of the air is probably right in the caliper - which should bleed out fairly quickly and completely.

 

The rubber seal is seated but it looks like there's a cut in it. I'll need to replace it i think