Di,

Good driving! Most dummies would have panicked and crashed. I am glad you had the presence and teaching that most do not. Always give yourself room to stop, which also saves gas and transmissions.

I don't like the idea of seeing smoke coming out of the engine compartment, but a stuck caliper will do that. It will generate enough heat to boil the brake fluid, creating air in the brake line. Fluid does not compress, but air does. So when you tried to stop, the air compressed and used up all of the pedal travel. Pumping the brakes put enough pressure to compress the air so that it would then allow pressure on the other three brakes.

Remember, only the front 2 brakes do most of the work.

Your mechanic will be able to replace the frozen caliper, last time I looked they were less than $80 at the dealer. I suggest also flushing the brake fluid AND the flexible brake lines, just to remain safe.

Unless you have a long drive to the mechanic, the brakes shouldn't get super hot and you can safely drive the car. Most of the air will have bubbled up to the reservior overnight. But you know your car and how it acts, so that is your call.

Again, good job!

Klaus
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Why are Volvos so endearing? Its just a car.