My jaguar x type 2004, I drove ot 60km and now my brakes and not working properly it goes flat but stop after a very long time, I noticed something as well, my rim and wheel nute were very hot I couldn't even put my finger for seconds. When I got back I check the brake fluid tank the next morning it was empty. I went to buy a brake fluid but it seems to not brake properly still the pedal is very soft and goes all the way down, only when flat then starts to brake slowly

 

Assuming brake pads and discs are still serviceable, start by bleeding the brakes....
No better....Check for vacuum leak to your brake servo.
If no vacuum leaks and the brake pedal still soft you might have to investigate replacing the short flexible brake hoses that go to your calipers - they can deteriorate with age and get "spongy" giving a soft pedal feel not unlike air in the line.

By the way....a bit more info would have been somewhat helpful (year, engine size, transmission type etc.)....even a hello would have been nice to see from a first time poster!

 

Several reasons for brakes not to work: 1.brake fluid old, I. E. Water in there. Water comes from the air. If there is a leak in your reservoir cap, that would be definitely the case. But this is not likely in you case, as you seem to have rapid loss of fluid. Actually, after you noticed a sudden massive loss of brake fluid, it would not have made any sense to ad brake fluid, as you have obviously a massive leak, which could be because of: 2. Broken rubber brake pipes (near any of the 4 wheels), 3. Broken metal brake pipe. 4. Leaking brake master cylinder or it's plastic reservoir, 5. Seals in the callipers might be leaking. 6. Leak in brake booster. Obviously, you have a massive leak somewhere and it should not be hard to locate it: just follow the leaking brake fluid...