Brake pedal goes to floor

Hey there! For starters i would do a complete brake system flush to purge the air. If the pedal feels spongy it means gasses are being compressed insteas of break fluid. What DOT did you put in there. I hope ot wasnt DOT 5.

How do I flush the break system I bleed the breaks starting at back pass side wheel then driver side back wheel front pass then driver I did that like 3 different times pump pump pump pump hold then open it did that each tire like 3 times each time I did it

when this started if it went to the floor, it may have been the master cylinder bad and bleeding all day wouldn't have helped and still not

Ya I was thinking that but I was also trying to see if it could be a sensor cause there are a few and I had issue with the brake light sensor before and I didn't know if that could mess it up

O and I used for 4 like it told me to online

I wish i could tell you exactly what the problem is... but sense i am on there i cant doag properly. But i can maybe gove you some info. In all honesty... i would have the dealership service it. (It can be a major liability) Im not too familiar with mercedez but on other cars only the manufacturer can do an abs service bleed which gets air out of the hydraulic control unit. (Hcu) im not sure if your vehicle even does that though. Also they can do a master cylinder bench bleed or diag if the master cylinder is bad the calipers are bad and a whole lot of other things. Now i cant see the car... but in theory if you are holding down the brake pedal while the valve gets opened and closed and the pedal still goes to the floor while constantly feeding the master cylinder brake fluid... you may also have a leak. It should be pretty obvious where it is if so. EricTheCarGuy and ChrisFix have some good youtune videos on brakes. You may want to check them out for more help.

I don't see leaks I checked again the pedal go's to the floor slowly and I pump it and it gets lil harder but I don't know if it's a sensor or what I hooked up a scanner and only code was mass air flow po100

I have a similar concern. I have a 2003, ML 350 that is otherwise in perfect condition. I've replaced the sensor, booster and master cylinder and the car still feels like it doesn't want to stop. The front brakes are at 7 mil. Even though I press the pedal nearly to the floor, it takes too long to come to a stop. The issue has been growing over the last 2 to 3 or so years. It began with the ABS ESP light coming on after which we replaced the sensor, twice. When the light continued to come on and the car didn't seem to want to stop, we replaced the booster. Afterwards, it continued to randomly come on if I hit a bump in the road. The master cylinder was just replaced today (not at the dealer) and the problem persists though the light did not come on during the test drive. It has been a great car but I want to sell it and get another. I am just hesitant to have anyone test drive it and decide against purchasing the vehicle. Order of repairs: sensor, booster, sensor, master cylinder

Having same issue. Replaced rotors, pads, calipers, bled system had dealership check it out they told me stop lamp switch, master cylinder and complete flush. Did all that. Same issue. Thinking it has to do with hydraulic system, not trying to buy new one gonna try and bleed that system next. Let you know tomorrow. Car is 1998 mercedes C230

Did you find your answer. I even replaced the auxiliary battery...its runs the brake pump and SBC unit but still no brakes here either same problem brakes to the floor no pressure...but no leaks...idk

I have a 2005 e350 no pressure and brakes to the floor...i have the red brake press pedal to floor fully warning also...i replaced the auxiliary battery which I didn't see anyone mention here...may be helpful to some. Its been known to cause this same code....my warning still persist

Same brake warning I mean

My issue above was resolved easily soon after posting the question. I apologize for the lateness, but CHECK your calipers ( make sure bleeder valves are always on top of caliper ) lol so funny, but Mercedes calipers will fit on either side. The thing you want to make sure is the bleeder valves are on the top and not the bottom. As soon as I switched them out no issues, brakes work great, nobody is gonna die!!! Life lesson learned.

I can't believe dealership didn't catch that by the way. Incompetence on them and myself.