Amazon: Evil Brakes

[devilishdesigner]

pulled out from the shops today and it felt like a rear brake was stickign slightly, kept going and it got worse and started pulling to one side like a flat tire, by teh time I could safely pull over the engine was struggling to beat the braking force. no flat tyres to be found, but my passenger side front brakes were locked solid, couldnt budge them. gave them a good whacking and levering, couldnt do a thing. they released after they had cooled for about 40min, but instead of risking it I got it towed to my mechanic, I have rebuilt brakes before, but dont want to do it on my daily driver, especially as I dont own a torque-wrench. has anyone had a disk brake seize on them before? any ideas what could cause it out of the blue? I drive the car all the time and besides slight variations in initial pedal pressure I have never had a problem with the brakes, they pull up perfectly straight and very effectively.