1999 S80 left front brake squeeling on smooth road

[sam matikesi]

Whenever I am driving on a very smooth tarred road, the left front brakes make a squeeling noise as if I am applying brakes but I will not be. But this stops immediately I step on a relatively course tarred road. What could be the problem.

[Oly_850]

Maybe a dragging caliper, how much meat is left on the pads and what do the rotors look like? When brake pads are worn down, the caliper piston is fully extended and can misbehave. If the pads are good and the rotors are smooth with no grooves, change out your brake fluid entirely with new DOT4. Old brake fluid gets full of moisture and doesn't have the same hydraulic properties.