yeup, more than likely a seized caliper ... if you leave it a while until it cools you wont be able to replicate the problem just by freewheeling it, whats happened is its warmed up, the pads have grabbed and everything has heated up and expanded like mad, gotten really hot, had one of mine on the xj on fire once, once it cools it frees up because all the metal shrinks until you hit the brakes hardish again then it starts all over again, tis shite behind the piston gaitor stopping it from moving inwards, on a grand the stinking rubber is probably a combination of all the shite the piston gaitor and the cv joint gaitor getting a bit warm.