PPalmer822

Hello everyone , this is my first post here . Be easy on me sorry if it’s long


I have a 2015 F-150 XlT 2.7l 36,000miles
its virtually new.

***the brake pedal goes to the FLOOR after being applied:


-Truck has all new brakes and rotors and all the calipers are working good.

-The truck stops great - slam on the brakes - it stops. Slowly hit the brakes - it stops. ( for now !?)

THE PROBLEM:

Like I said the brakes stop great however once at a red light or stop sign - my brake pedal goes to the FLOOR.

-I have never opened the brake fluid reservoir and it is up to the max. There are no leaks anywhere.




**i have been reading things like possibly the master cylinder , brake booster , or the hydraulic control module , or air in the system ...

where do do I start without spending $$$$
I am mechanically inclined and have access to everything I need ( lift tools etc ) I’m just not sure where to start on this one .

I was going to start by bleeding each wheel and checking for air ? But if there’s air - where is it coming from ?

Has anyone encountered this issue ? Could it be just a master cylinder leaking back by the seals or air in the system ? Seems crazy on only 36k miles



I appreciate any help, thanks everyone .

cheers !

RLXXI

Sounds to me like the master cylinder is leaking past the seal internally.
.

raski

Air will not be in the system if you didn't open a bleeder or line. As mentioned, you likely have a bad master cylinder.Don't bother bleeding until you get that replaced.

pjazz

I'd try bleeding them before buying a master cylinder.

DarrinT04

i would too