F350 with braking problems

Hi I'm having the same problem as quoted below, I have no clue as to what it could be. If you have any idea would you send me an email, I would greatly appreciate it. Thanks. [email protected]

Hi, I have a F350 with break problems, and can't figure it out. Problem is that when the truck motor is running, and pressing on break peddle, it will slowly go to the floor, in the pass on my vehicles, this ment that the master cylinder was bad and bleeding back through,... however I have replace the master cylinder with a new one, and still does it. I have also replace the ABS cylinder on frame that goes to the back break too, and no help. I have bleed breaks several times, but still no help. When motor is off, peddle seems solid, but when motor running, with vacum buster is working, then pressing on peddle and holding it, it will slowly go down almost to the floor,..... anyone else had this problem, or any ideals that I may not know about?

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i'd reccomend you take it to a dealership or specialist.

it could be a problem like air in the brakes, they may need to be bled. your vacuum system or lines may have a problem, so check them all too. i wouldn't say it's the booster because if that was failing the pedal would be much harder to puch down, although if that's failing there's a possility there's a leak or something there.

sounds like a vaccume leak to me, check all hoses