Apologies in advance for the lenghty post. Hi guys, hope someone can point me in the right direction. Car is a W212 E350 CDI 2012. The pads were due a change and the discs had some life in them but deciced to change everything in one go. Alloys needed a refurb so had them sent off. At this point i decided i would also remove the calipers and get them re painted by the alloy refurb place as they also painted calipers. (well known reputable company) The calipers were received back with no issues. All seals good. Everything was covered up which needed to be covered before painting. Please note, the calipers were not stripped or taken apart. I put everything back together, calipers, pads, discs etc. Discs and pads are genuine parts. I pressure bled the system the text book way- furthest from the master cylinder etc. I used a pressure bleeder, no pedal pumping. (i have changed discs and pads, and bled the brakes too many times to count, so this is not a case of lack of experience). I also changed the pads and bled the brakes on this car before without issues using the same method. NOW, after completing all the work, the first test drive immediately told me the pedal was not right. There was no biting point and the pedal travels right to bottom before it bites. Not right. So bled it one more time. Improved slightly but the same issue remained. A mistake i feel i made- i did not plug the brake lines once the calipers were off. The flluid in the system was drained. Excessive air must of got in the system or in the ABS pump. But multiple bleeds should have got this out. When pushing the pedal multiple times, the pressure builds but gradually goes and pedal sinks again to the bottom if you stop pumping. At this point, i gave the car into Mercedes. They maintain the car yearly and are familiar with the car (just to keep the service history). They have bled the system using their official method, machine and run the abs pump while bleeding to ensure all air is out. There are no leaks. They confirm everything is fitted correctly, parts are all correct, servo is ok. They are stumped at the moment as am i. They will be getting a 'specialist' technican in tomorrow to bleed the brakes at a much higher pressure using another machine. Would anyone have any ideas at all what could be the issue?