Deore Disk Problem

[Morryjg]

I have Deore disks on my Enduro. This weekend on my ride the rear starting screeching like a banshee. So after some inspection we found that one pad was worn completely, there was no pad left. The other pad was in good shape. After playing with it a bit we figured out that one piston was not firing correctly. It would move a bit, but not enough to work. The theory is the one piston was firing and having to push the rotor over to the other side so it could squeeze the rotor. Hence, the reason why one pad was gone and the other was not.

Has anyone else had this problem? Do you think it is an issue that Shimano would warranty?

[Repack]

I would guess there is something else going on. In order for the wheel to slow down, both pads must be pressing against the rotor. Even if one piston is completely seized, the force from the other piston will flex the rotor over.
I know that the newer Deore discs use 1 sinthered metallic pad and one organic. Don't know if one tends to wear faster, but I would think the organic would. Are/were the pads old?
Just a thought: If the questionable piston is also the one with the worn pad, I wonder if the miss-firing issue could have been cause by heat.

[Morryjg]

The pads are only about 8 months old, and that's not 8 months of riding. The pad that wore out was the one doing all of the pushing, the pad on the piston that wasn't firing was okay.

[RD]

Shimano has also had some problems with bad bores for the pistons in their calipers. I encountered a faulty one with an XTR yesterday. Odd. I think REPACK is right though. Shimano now recommends to use the organic pads (sticky) ones in mud and wet weather. In the XTR literature and 2003 service manual, they oddly claim to have produced a metallic pad for noise reduction. Odd as well.