Ok so the piston literally popped out brake fluid spilled all out. I accidentally hit the piston while i was removing the knuckle. I put it back in, and the plastic seal isnt ripped. Just wondering if it will mess up due to it popping out. Or is everything ok? Do i push it back in with a c-clamp? Im a noob and know nothing of this so any useful information will help. Thank you.

 

I am more interested in how you got it back in with the line still attached...unless it never came all the way out.

...but anyways, as long as you didn't mess up the inner or outer seals you will be perfectly fine. Press it back in and bleed the brakes like normal.

 

What he said. If the seal is not ripped, press it back in. If the brake fluid level wasn't at the bottom of the reservoir, you are home safe. If it was, you may had draw some air into the system, Hence, require bleeding.

 

The picture you posted looks a little strange to me. When I've rebuilt my calipers (ITR/Honda V6), the part of the piston near where it contacts the brake pad has a groove to hold the dust boot, and the piston is hollow on the end that contacts the pads. Your picture doesn't show the groove, but maybe the piston is just different on yours, or maybe it is actually in backwards. When I've rebuilt my calipers (off of the car), the biggest pain is trying to get the dust boot to stay attached to the piston, but I found a YouTube video that helped. Anyway, did your piston have a groove on the outside for the dust boot?

As far as pressing the piston in, I use the following type of tool for my brake work on my Honda or my Audi (for stock or Brembo 4-piston). There are cheaper copies on E-bay (I paid over $30 years ago), but the following one looks pretty similar to the one I bought. FYI... - Jim

Mercedes Benz BMW VW Audi Disc Brake Pads Caliper Piston Press Spreader Tool | eBay

 

Thanks everyone I got it fixed!

 

Its pretty standard and nice to actually tell us HOW YOU FIXED IT so when people find this on a search they can actually be helped by your thread!

 

Well I removed the piston and the boot was ripped. So I bought a new caliper and just replaced it! Even though my caliper was from a 96 jdm ITR the GSR caliper was the same exact thing so no problem there.