frank122376

is it the booster?

digitaltrucker

year, make model mileage? Could be, could be air in lines? More info please.

frank122376

well it started with a break line, i changed it, tried to pump up the breaks and i heard something give and the pedal sank to the floor and now no break pressure. i changed the master cylinder and still can not build pressure even enough to bleed. truck make and model is a ford f150 1999 4.6l 2wd pickup has about 235000 on it

frank122376

not leaking anywhere and not losing fluid

NFortin1966

Did you bench bleed the master cylinder before installing? If not, you are going to have real problems with the ABS system once air gets into it, if it hasn't already.

who_knos

I agree more info would be great......I had the same thing happen and it was the steel line to the rear end, but couldnt see the drip till it soaked all the way through the dirt in the frame.

frank122376

well turns out it wasn't either one of those, that i know of, i found another leak in the flexline coming from the master cylinder into the manifold below, replaced line, have brake pressure now. I did bench bleed the master however i fear having a hole in that line in combination with pumping the brake pedal may have let more air in, is this assumption correct and if so how do i fix it, other than a standard bleed form calipers and cylinders in the back, it does have drums btw

frank122376

also discover that the brake booster that i changed had a previously installed part that was not correct how ever i don't know if it makes a difference. the booster that i removed was for disc brakes, not drums, how much affect does this have on the system if any.

frank122376

wanted to also say that i did not see that leak until i had replace the booster and master cylinder

RLXXI

If you have 4wabs your going to have to do an electronic service bleed on the hcu. This can be accomplished using Forscan or IDS.

www.forscan.org it's a free download, you must get a usb/obd2 dongle and use it with a windows tablet or laptop. .