Front caliper piston won't budge?

[YZThumper]

I have an 01 KX250 and I'm having trouble with my front brake caliper. As I was changing brake pads I noticed one of the two caliper pistons isn't moving when I pull the brake lever. The other caliper piston seems to move fine when the brake lever is pulled.

I decided to pull both pistons out of the cylinders and clean them to make sure corrosion isn't the issue. I reassembled the pistons in the opposite cylinders from which they were pulled (for comparison) and it now the opposite cylinder (with the problem piston) won't move. This seems to indicate the piston, not the caliper cylinder is the issue. Has anyone ever seen this happen? How does a brake piston go bad?

 

[marcusgunby]

If you hold the one that moves you should see the other work instead-normal operation.

 

[YZThumper]

Thanks Marcus, you put my mind at ease :yeehaw: . Went out to the bike and did as you said, and you are absolutely right. Never realized that about a double piston caliper. Thanks for your quick reply :cool: