Brake Fluid light, then no brakes! - Page 1 - Boxster/Cayman - PistonHeads UK

Pretty much as above! Driving, brake hard. Next roundaabout 'ding' brake fluid light, pedal to the floor only braking for the first inch or so of pressure. It was on the way for an MOT anyhow, but any thoughts what it may be? Cheers

It might be a split brake pipe...older porsche hydraulic lines suffer badly from corrosion. ( quite disappointing considering cheaper cars eg VW never do) I would look under car first for signs of brake fluid leakage. The line that runs front to back is a common suspect , especially at the pipe to body clips. A leak anywhere under car will be easy to spot. Ian

Certainly a loss of hydraulic pressure somewhere. As above, could be lines, flexi pipes, etc.

Happened to me in a race at Oulton Park once The flared end of a pipe had fractured off, right inside the ABS unit. The union had to be un-done as normal and the broken off end then fished out. We only had a clue what had happened by the leak under the car, but that wouldn't have happened on a road car with all the boot floor bungs still in place. So if you can't find an obvious leak look there.

A section of the pipes front to rear on the passenger side is obscured by a plastic cover. While the rest of the pipes may look intact, they often rot behind the cover and go unnoticed.

Working in the last inch of travel sounds like a component failure rather than fluid loss, to me. If you had drum brakes at the rear Id suggest that the shoe had come away from the cylinder, but in a 4x disc car its going to be a little more involved. If you had a fluid leak then a couple of presses would have drained most of it and thered be no brake action at all.

Brake pipe burst, one that goes back to front. Both sides replaced & MOT passed for £140. Felt lucky getting out at that price, so got new disks and pads as advised for the front!

Cheap and lucky, but Im surprised that you missed the fluid.

Good to see repair done at reasonable cost. Your initial description is the usual symptom of a split brake pipe from either corrosion or abrasion. The hole in the pipe usually very small so when you brake the volume of hyd oil pumped by the master cylinder is well in excess of leak rate. This gives a soft brake pedal but much reduced braking effect. Catastrophic failure of pipe i.e. full bore leakage from pipe with no braking available is rare except in accident damage. In today's high tech driven car market I wish the car manufactures saved a few pounds on the unnecessary trinkets and spent it on better materials for safety systems. I'm sure to fit a car with corrosion proof brake lines ( i.e. A higher spec material) would not be more than a few pounds per car......many of the lesser priced cars have done so long ago , so why not a prestige make like Porsche?

Lack of brake fluid changes also causes brake pipes to rot from the inside out. Poor maintenance is as common a cause as manufacturers material selection.

Never seen corrosion from inside out before , very interesting......I'm guessing the oxygen needed to create corrosion is entrained within the water to start it off....good info. However if material was corrosion proof the the entrained O2 /water mix would not effect pipes but I suppose would effect other vulnerable parts. Got to agree quality , regular maintenance in braking system can only be beneficial. Thanks

Should note it hadnt been driven for 6 months and was on its way for MOT...