My 2006 Sprinter suffered brake failure whilst in France with brake pedal hitting the floor. Taken in to main dealer who diagnosed dud master cylinder and replaced with new. It was ok for journey back but the next driver reported that pedal had excessive travel as he arrived in the yard. I went to check and the brake pedal went straight to the floor. Brakes were bled and lots of air came out of rear right. Since bleed nipple flats had been rounded off by French dealer we assumed it had not been fully tightened and had admitted air. System bled fully and seemed ok. All well for another couple of hundred miles and I suffered pedal to the floor yet again. Once again, lots of air in rear right. No messing this time. New callipers all round as now 13 years old. Another 150 miles or so and it's happened yet again. I'm now replacing both pipes and the load valve which are the only things on that corner that haven't been replaced. Anyone else come across anything similar?