While I agree with those telling you not to drive it til you get it fixed, I wanna point out that there may not actually be anything wrong with the caliper. The hoses at the wheels will occasionally decay and start acting as check valves. They only cost about ten bucks. If it is the caliper, while the timing looks bad, they don’t give signs that they’ll soon fail. They just let you know when it did happen.
This is true.
However, whether it turns out to be a deteriorating brake hose or a bad caliper, Jim needs to have both the rotor and the brake fluid replaced. The overheated brake rotor and the boiling brake fluid are both no longer safe to use.
True, and I probably should have included such possibility in my response, but my goal was to get the OP not to drive the vehicle until it gets repaired. The details will get (hopefully) found and resolved by the shop.