Hi all,
I got in the ute this morning to go to work, and as I reversed out of the carport, I touched the brake pedal only to find it was rock hard, and the car didnt stop. I pushed really hard on the pedal and the car stopped slowly. I pumped the pedal a bit and it didn't get any better, but the brake alert light (!) came on as the pedal was pressed. It went out with the pressure off the pedal.
The master cyl was still full, and the brakes worked fine yesterday (and for the last eleventy years)
so I am at a loss to explain this. Do I need a new master cylinder? Or what?

check the hose that goes from the brake booster to the intake manifold for splits/holes etc.

How's it feel with the engine off - you should have couple of applications of the booster after the engine is turned off.

The line to the booster is OK, no vacuum leaks.
The brake pedal feels the same with the engine on or off. I held pressure on the pedal with the engine running, and switched it off, no change. Pumped it a few times. No change. Then I held pressure on the pedal and started the engine. No change. I reckon the booster is roo-ted.
The (!) light on the dash is what confuses me. The fluid level is fine, and it only comes on when there is pressure on the pedal. It doesnt stay on at all.
I am going to fit the master cylinder and booster out of my donor ute, as a unit, tomorow. It was working fine before I started pulling it apart, so it will get me going again, I hope.