Hello guys, new to the forum here. Been lurking for a couple of days now trying to figure out the brake problem on my 02 f-550 7.3 wrecker truck. The pedal started going all the way to the floor one morning right after I cranked it. So I changed the master cylinder and it was still doing it so today I changed the hydrobooster ? I think it's the name and I figured out that the problem is that the rear wheels DO NOT lock up. Only the front. Any tips and ideas will be greatly appreciated! Thanks in advance.

 

You might get a faster answer if you go here: https://www.ford-trucks.com/forums/forum232/ That's the "BIG Truck" forum. Maybe Scott (senix) will move it for you.