Destroyed brake caliper piston (1 Viewer)

[GerhardUngerer]

I did some brake-work on Dobbie today. It all went well until I got to the right rear (last stop). I could not get the caliper off for the longest time. When I finally got the caliper off, the pictures below shows the condition of the piston. There's the catch. The brake pads were in really good condition, so it had to look this way before the pads were replaced. Had I not put new rotors on, I would not have known.

Question. HOW? I can't see any way for this to happen with the brake pads in. Even if one brake pad disappeared and the piston pushed against the rotor, the rotor would have had deep scarring. It didn't.

Another question. Who just puts this back on?

 

[Grandlooser]

It was probably contacting a rotor earlier in life. Honestly it doesn't really effect caliper function, however my own ocd would have me turning the piston on my lathe or just replacing caliper.

 

[GerhardUngerer]

It was probably contacting a rotor earlier in life. Honestly it doesn't really effect caliper function, however my own ocd would have me turning the piston on my lathe or just replacing caliper.

I am going for door number 2. New caliper, or at least new caliper piston.

 

[Grandlooser]

You'll probably be pissed at option 2. Getting the seal back with crusty rotors is a total bitch.

 

[Kernal]

I would replace both rear calipers so you know you have a good pair working together. If the pad on that side was less worn than the other it suggests that the piston was stuck.

 

[jonheld]

Calipers can be rebuilt using all OEM parts. A new OEM rear piston is around $20.
No need to replace the calipers unless they are physically damaged or badly corroded on the inside.

 

[TerraNerva]

What Jon said ^^ Rebuilt my fronts with all new stuffs, only to find the lower bolt on front driver side was stripped...