Disappearing brakes - at totally random intervals - weeks even months apart, when i go to brake my brakes fail. The peddle goes all the way to the floor. In two instances recently [approx 2 months apart] I had to brake more harshly due to drivers cutting into the road, and when I have ‘slammed on’, my brakes peddle goes all the way down, making a strange screeching noise, and unable to stop for some time. I then set off, and when I brake after, the peddle goes all the way to the floor still. When I pull over and try tapping the brakes upto ten mins later, the brakes are totally seized up and tight. I take it to a garage and they cannot find a solution. I have had new brake pads, discs and a rear cyllinder all in the last 6 months. The problem of totally intermittent brake failure continues. I have so so nearly crashed twice now into other cars as a result of it and have been extremely lucky not to but I fear for the next and I dread braking. ABS does not flag up as kicked in on my dashboard in any of these instances. If it were ABS it shouldn’t be as these are brakes in dry road conditions/normal.
Sounds like you may have a sticking brake caliper. This can cause excessive heat build up in braking components thus causing the brake fluid to actually boil in the caliper. Boiling brake fluid introduces gas into the hydraulic system. Gas is compressible so this leads to a soft or no pedal condition. ie. no brakes. Then after you’ve stopped for a while, every thing cools down you have a pedal again.
This is a very dangerous situation and you need to get it fixed yesterday. Take the car back to a competent mechanic and have them look for a sticking or seizing brake caliper.
It sounds like the brake master cylinder is leaking internally.