Brake piston

[dreamaker]

Is there a special tool for extracting brake pistons out of the caliper for a Valk.

Dan

[Rosie]

Just rebuilt my front calipers. I used a shop rag in front of the pistons then I blew them out with air pressure. start out with low pressure then crank it up till they pop out.

[Pete]

Watch your fingers as sometimes the piston comes out with force.

[hubcapsc]

And wear safety glasses... there's still a little brake fluid in there... last time I forgot to tighten the
bleeder back, and when I blasted air into where the banjo bolt goes, the brake fluid shot out under pressure
from the bleeder in a fine mist - it was weaponized!

-Mike

[dreamaker]

Well I didn't think of air, I just used the fluid pressure. I got everything done, I just wondered if they made some sort of expanding tool or not.

[dukesguy]

I just did mine 2 weeks ago. I know the right side caliper was dragging. I used a paint stirring stick to keep the pistons from flying out. One of the pistons came out with air pressure easily. The other one wouldn't budge. I tapped it back in to the bore a tiny amount, still wouldn't move with the air pressure. I ended up hooking up the banjo bolt to the caliper without mounting the caliper, bled the caliper, blocked off the piston that would move, pumped the brake lever to push out the stuck piston.
Be sure to pump the piston until it hits the paint stick. Cleaned everything up with fine sandpaper, new seals , reassembled, and tested with air pressure. Everything worked fine, and still does. Never grab the piston with pliers or vice grips to get it out. It will possibly ruin the piston.

[hubcapsc]

Never grab the piston with pliers or vice grips to get it out. It will possibly ruin the piston.

I finally resorted to that, on the first rebuild I ever did... stuff was so gunked up that the brakes were stuck
on while I was riding. It certainly ruined the piston! But I had another piston handy...

-Mike "from an Interstate - D'OH!"

[Rosie]

I have made fittings for cars where you adapt a grease zerk to fit the bleeder fitting then plug the banjo hole with the bolt. Hook up the grease gun and pump them out,works great but messy.

[hubcapsc]

I have made fittings for cars where you adapt a grease zerk to fit the bleeder fitting then plug the banjo hole with the bolt. Hook up the grease gun and pump them out,works great but messy.

I'm finding it easy to imagine the "works great" part and hard to imagine cleaning the "messy" part out of the caliper   

-Mike