Motorcycle Repair: front brake lock, yamaha maxim, brake calipers

Question
Hey Chris,

I have an 85 Yamaha Maxim XJ 700. One of the front brake calipers locked as I was riding, and I had to remove the pads on that caliper to go home since the pistons would not go back at all. I was told that this usually happens because of buildup in the caliper seals. So I opened the calipers and cleaned the seal seats (there was quite a lot of buildup) and then replaced the seals on both front calipers. There was no rust inside the cylinders, and the pistons had no pits in them. The pistons slid back in with minimal effort.  I  connected the brake lines and bled the system. The brake was working fine for 20 minutes and then that same caliper locked up again just as before. When I removed the pads I saw that one piston was pushed out more than the other. Also, both pistons had come out unevenly out of the cylinder. Any ideas? Thanks,  

Answer
Hi Erion.
 Clear the brake lines.  Flush them out really well.  Bleed the system and try it again.  If it is sticking like that, then the problem could be something in the system preventing the fluid to return properly.

Let me know what you find.
Good luck.
FALCON