Skoda Fabia MK1 1.4 Brake Failure

Hey all.

Not sure if anyone else has had this happen to them or their Fabia. I've got a Skoda Fabia 1.4 2000 MK1 and have been having some issue with the brakes over the last few months.

Firstly the brakes failed (Pedal dropped to the floor like a clutch and did nothing, upon release and breaking again they worked fine) I was doing a long journey and forgot about it by the time I got back. However it then happened again about 700 miles later, this time a shorter journey. I took it to a garage and we couldn't get the issue to be reproduced. Ended up replacing the Master Cylinder and all of the break fluid.

Everything seemed ok after that... (800 miles later) I did around 2.5 mile journey and all 4 breaks locked on... I was close to the garage so struggled it straight there, by the time I got there the front wheels were smoking and the back wheels were very warm. After cooling down over night the breaks unlocked and the car drove fine again no issues couldn't get it to happen again.

Mechanic is confused as he has checked everything and there are very few parts left to go wrong!

Long shot but if anyone has any ideas or this has happened to one of you before I'd love to hear from you!

Thanks