oops....

while my front wheel was out so i could put on a new tire, the bike slipped off the centerstand and I grabbed the handlebars super fast to stop it from falling.

Unfortunately, I grabbed the brake lever too. Now my calipers are in the full on position all the time, with the brake piston fully extended.

how do i remedy this blunder? i don't have to rebuild the cylinder/piston do i?

 

That's interesting. I think I would take off the cap and open the bleeders just a little on each side to relieve some of the pressure, close them off (like when bleeding brakes) and then check to see that the fluid it pumping back up to the top when squeezing the brake handle.

Just an option to see if there is a quick fix.

 

If they're not popped completely out, which it sounds like they're not, you can press them slowly back in with a C-clamp.

With two calipers you'll need two C-clamps, or something else to keep one from popping out when you press the other one in.

Had to do this myself recently.

 

i understand that i put the clamp on the piston and tighten it, but do i need to open the valve or anything like that?

could you explain a little further, perhaps?

 

You could go ahead and loosen the top of the master cylinder, and wrap a rag around it; then slowly squeeze the pistons back in.

Once everything is back together, I would bleed the brakes in case you picked up a bubble or two in the course of the little escapade.

 

Don't skip the rag - brake fluid will eat paint. As Fitz said you have to open the master or you are just creating pressure in the system.

If you completely remove the top you risk a fountain of brake fluid

 

I didn't loosen anything. The passages for brack fluid are small, but there's no check valve. The fluid is supposed to be able to flow back into the MC when the lever is released as the piston gasket pulls the piston back.

In other words: there's nothing else to explain, just put the clamp across the piston and turn the screw slowly to push the piston back in. If you go too far back, you'll need to pump the brake a bit to reset the piston to its correct location, though.

 

i can attest to that.

 

sweet thanks fellas