Originally Posted by snrusnak
A quick and dirty way to check if a caliper is sticking is to go on a highway speed run (time depends on how bad the drag is...may only take a few minutes, may take several minutes) and then get off at an exit and immediately pull over and feel with your hand left and right front wheels. If one is much hotter than the other the caliper is likely sticking. I personally would rebuild it before replacing it, however you can replace it. Again, I personally would do both sides at once. Next thing to look at if that is actually the issue is the rotors.
^^That's a very good point^^ and how I usually check. lazer probe works good too. I had a less that ingenious friend squirt water on his from a drinking bottle and I actually heard the "plink" when he cracked his rotor.
My RF caliper was sticking and I replaced them both...2 miles down the road it started dragging even worse. Cracked the bleeder and more air came out.
Over the next week or so I still noticed some drag.
Turns out the hose was bad. (Flexible brake line)
If you take a plastic drinking straw pinch it in the center and blow through it...you can force air out. But what happens when the fluid is supposed to return? One way flow and the caliper stays pressurized.
Just thought I'd throw that out there for consideration.
Was the only example I could come up with. I usually try to give examples so it doesn't sound odd just saying you've got mud in your tires.