Hello,

My old caliper was so bad I didn't find it worth the effort to clean and rebuild so I bought a new one few months ago and replaced it along with rotor and pads and fluid.

Recently I've seen brake fluid on my rotor and my brakes are spongy. I know there's a leak because I park it on a sidewalk and I can see the fluid lubricating the floor.

Is it likely I just need to replace the seals on the caliper piston or should I just try bleeding the line with fresh DOT4? Could something else cause the fluid to bleed through the seals such as moisture?

Appreciate the wealth of knowledge here. Might have to start making short videos for the Youtube.  

Appreciate the troubleshooting advice. I was just thinking caliper seals because I can see fluid on the rotors but that might be because I took it for a ride and noticed it afterwards.

I'll make sure to do all the troubleshooting as advised.