Brakes went to the floor...

[Casiofi]

Having adjusted the clutch linkage at my Dad's house (big garage and endless tools!) I set off back to Aberdeen, and within about 5 miles the brakes started to feel a little odd. usually there's about an inch of free play, before you can feel the brakes, and the pedal is still well off the floor before it locks up. But this time, the first half of the pedal it felt quite stiff, and after that the brakes came on quite sharply, much closer to the floor than before. It felt almost like the brakes were binding, with slower than usual acceleration and struggling past 55, but I stopped every 10-15 miles and checked the wheels and the drums weren't getting hot. So I soldiered on to about 5 miles from my house where I stopped for petrol. Leaving the petrol station I pumped the brakes a few times, just to see if it would loosen the pedal up a bit. And suddenly the pedal sunk right to the floor, the stiffness had gone, and the brakes were barely working. Managed to get it home, tried pumping the brakes to see if it would build up any pressure but no dice. It's dark right now so I haven't looked into it any more, but any ideas where I should start looking? My first thought is to check the m/c and brake lines for any evidence of fluid loss, but I'm a complete novice when it comes to the braking system.

[oliver90owner]

There are two failure modes regarding the fluid level in the master cylinder. Empty and it is likely the master cylinder has pumped all fluid through a leak somewhere in the system. Full means the master cylinder is at fault by not pumping fluid to the brake cylinders.

[panky]

Check behind each wheel, if there's a wheel cylinder gone you should see fluid dribbling down the inside of the tyre, or from the chassis rail if the master cylinder is leaking.

[simmitc]

If you have lost fluid, then apart from the cylinders, any pipe could fail. Right beside a union is common for metal pipes, or a flexible hose could have split. Again, should be obvious when looking under the car.

[bmcecosse]

First check - has the master cylinder level gone down? If so - as above - look for leaks.... If not - likely to be master cylinder seals failed.

[Casiofi]

Thanks all for your replies. The car has been put to the back of the garage for a couple of weeks as I have some rather important exams soon and I don't have the time or energy to start another job on it. However, I had a quick look under the front and couldn't see any evidence of leaks, the front pipes have all been replaced within the last two months and looked good. I'll update this when I start investigating properly!