It's Avid mechanical. Just recently, it was locking up smooth & nice til yesterday it stopped locking up. It does lock up but with added force it slips. I even bought new pads and adjusted the alignment to make sure it's parallel to the disc itself. What would cause this? Am I spacing this right? If I'm looking my disc brake from the rear where should the pads be located (cause only one side of the break pushes against the pads: ] | [ <- like this? or... ] |[ <- like this? ...this is really odd and having a headache! I did notice my disc is slightly warped...slightly. Would that be the problem? HELP!!! BTW I'm using Avid brake levers...forgot which model but it's the cheap $40 version. I didn't have this problem for awhile with it either...XT levers didn't last long.