When a caliper problem shows up, the next step is figuring out which corner is at fault. A few simple checks point to the bad caliper. Here is how to tell which caliper is failing.
Feel for the hot wheel
After a short drive, carefully check each wheel for heat. A dragging caliper makes its wheel much hotter than the others; see sticking caliper. A burning smell from one corner is another strong clue; the hot corner is your suspect.
Which way does it pull?
Under braking, the car pulls toward the side that is braking harder - or away from a caliper that is not applying; see pull when braking. Combined with the hot-wheel check, the pull direction helps confirm the side.
Check pad wear and spin
Uneven pad wear side-to-side, or one pad worn far more than its partner, points to that caliper. With the wheel off the ground, a caliper that drags makes the wheel hard to spin by hand while the good side spins freely; see do calipers wear out.
Confirm and fix
Look for fluid leaking at the suspect caliper too. Once identified, replace it - a loaded unit is quickest; see are loaded calipers worth it - and always do fresh pads and service the rotor. Fit quality pads and hardware.