VT - Brake Problem!

[ironwool]

'99 VT Commodore Acclaim - Driving the other day , it started making a sound like a flat tyre, i checked the tyres and no flat. When i started the car again the brake warning light was on (handbrake was off), after pulling handbrake on and off and working the brake pedal for about 30 seconds the warning light went away. Started driving again and the sound was still there, and about 3-4 kms later the brake pedal became spongy to the point where it had to be pushed floor to get any stopping power. Pulled over again and checked brake fluid (was fine), and decided to let the car cool down for 30mins. While i was sitting there the brake pedal became stiff and wasn't able to be moved at all. After the 30mins i turned the car on and evreything was fine. Have taken all four wheels off and checked pads and rotors and it all looks fine.
Could this just be a once off thing; or is it a master cylinder or caliper cylinder?
Any help would be greatly appreciated!

Edit - The noise appeared to be coming from the left hand side.

 

[aussiepride23]

if your car has hubcaps check that lhs hubcaps dont have a broken lug or try changing them all around as for the hand brake light make sure your brake fluid is up to level