So I had to do an emergency stop just now. Luckily only doing 30mph. Luckily as the ABS kicked in, then thud and the pedal goes to the floor and no brakes

Immediately knew what had happened. Sure enough it looks like the passenger side front to rear pipe has burst and dumped all the hydraulic fluid.

Looks like this week's job is replacing front to rear pipes both sides. Go on, how much of a PITA are they to do? 2004 Vogue TD6 - Remapped
2008 Porsche Cayenne S
1998 Lotus Elise

Wow, nasty! How did you know which brake pipe had gone?

Both front to rear pipes run down the passenger side

http://www.fullfatrr.com/forum/topic25799.html .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

The soaking of brake fluid under the passenger side sill and trail of fluid along the road gave it away!

Cheers joe90 was just reading your write up.

Could have been worse. An 80mph stop with all the kids on board  2004 Vogue TD6 - Remapped
2008 Porsche Cayenne S
1998 Lotus Elise

Surely it should have dual circuit brakes like other cars and vans, usually paired diagonally opposite front left, rear right and vice versa? It sounds more serious than a brake pipe failed, it would have to be two pipes failed or something else. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

No dual circuit brakes.... .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Really? I thought that was a legal requirement under the construction and use regulations. My flabber is well and truly gasted. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

Don't know but all I can say is not enough braking force to hold it back from the creep of the auto transmission. 2004 Vogue TD6 - Remapped
2008 Porsche Cayenne S
1998 Lotus Elise

I assumed the same that the brakes would be dual circuit and work to some extent. But no. Never had brake failure before, had classic cars where you get the precursory weep, but this was very sudden 2004 Vogue TD6 - Remapped
2008 Porsche Cayenne S
1998 Lotus Elise

Before anyone wades in I am going to qualify my remark. The FFRR does have dual circuit brakes, but does not have two(dual) brake lines running to each corner. The split reservoir system in the master cylinder is supposed to provide limited braking effort in the event of a fluid leak.

From RAVE:

Click image to enlarge

Thats what I was meaning, dual circuit brakes are normally split front left and rear right paired, front right and rear left. A broken line will drop fluid from one circuit but not the other hence my comment that even though one line had failed, the pedal shouldn't hit the floor and there should still be a reasonable amount of braking. BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

Providing the rest of the braking system is serviceable

If the pedal hit the floor then you likely have some other damage. If the fluid is down that side then it could be that the fault is causing the fluid to run along the outside of the pipe

It is also possible as prompted by mikey that only half the system had been working before! BMW i3 Electric Car
2012 Full Fat RR 4.4 TDV8 (now gone)
2006 VW Touareg 3.0 TDi V6

Its happened to me, and yes the pedal plummets to the floor. I wouldn't overly worry about other bits being broken at the moment. It even says that in the linked image that pedal travel and brake effectiveness will be affected.

The pipes are steel. They rust and when they do, their pressure capacity threshold lowers. Under normal gentle braking, the pressure may be below the strength of the rusty pipe. Ram the brakes on, and you blow right past that threshold, and the pipe splits and they fail pretty instantly without warning.

If one has rusted out, then its reasonable to expect the others to do as well. I'd recommend you're 'in for a penny, in for a pound' in this job and replace:

- the pipes that run from the front wheel well along under the passenger sill
- the pipe that runs across the top of the axle area from passenger side to driver side.
- the flex pipes that run down the suspension arms to the calipers.

The pipes are fairly easy to replace. I did my runs with copper pipe as that's what I'm used to using. Others have bought the pipe pre-formed from the dealer ... not crazy prices.

I do buy the genuine flexi pipes that run to the calipers though. So much easier to fit. V8 or else ...