Not very long. Hose is a real possibility. So is a seized caliper on the right side.
We can speculate forever, but it's obvious that you'll have to take the front brakes apart and see what's going on. I think you'll see the problem pretty easily once you do that.
I seem to remember that this car was sitting for a long time, right? I think it would be prudent, even without problems, to take a close look at the brakes and renew all the bits that deteriorate over time. Like, for starts, all the rubber parts in the hydraulics. It IS the brakes, after all...!