smkettner wrote:
Pedal to the floor always said time for a new master cylinder to me.
Never said brake rotors. In this day of electronics the simple mechanical things are easily overlooked.
Not so fast on the MC.
OP stated in the first post..
"It's been a while since I posted but we continue to have brake issues with our 2012 F150. At low mileage the front rotors needed to be replaced.
We've had continual problems with the brakes not pressurizing correctly on start-up of the vehicle-brake pedal goes right to the floor until it's pumped a few times. We had the vacuum pump recall done which alleviated the strange noise we were getting but the brakes continue to have the same issue.
When the truck is not running the brake pedal doesn't budge at all.
My experience on previously owned F150s is there's at least a little bit of play when you depress the pedal upon starting the engine.
Thoughts?
It's going back in the shop next week and any suggestions on what direction in which to guide Ford would be helpful as the service advisor seems a bit clueless. Thanks."Note, I broke the OPs post into paragraphs to help make it easier to read..
Notice the part I bolded?
That is an important key.
IF the MC was indeed bad (IE internal bypass from worn or defective internal parts) then one would not have a full solid pedal when the engine is NOT RUNNING. If MC is bypassing internally the pedal would hit the floor BEFORE the engine was started..
OPs pedal is hitting the floor AFTER the engine has been started.
OP has already had the vacuum pump replaced (I am assuming it is a "eco boost" since it would not develop enough vacuum for the vacuum booster).
One needs to look at the things PAST the MC..
Since the OP did not mention any loss of brake fluid I would rule out wheel cylinders, brake lines and hoses leaking..
So, that now leaves the ABS module, anti-sway module and possibly the traction assist module as possible culprits..
All of those modules have some sort of direct connection to the brake lines and brake fluid circuits..
As far as rotors goes, well they are "wear items" and sometimes you don't get the wear you should get..
BUT, I would highly recommend checking the brake pads fit in the calipers. I have run into issues with the pads fitting way to tight in the calipers. So tight that a light rust on the pad edges will freeze the pads and the caliper can not longer push the pads correctly. This can lead to the pads hanging up and dragging on one or both sides.
I file the tabs on the ends of the pads until the pads slide easily in and out by hand..
Lost a set of front rotors on a 2003 F250 because of this issue.
Check front AND rear pads for this issue, it is possible the rears are frozen and all the stopping has been on the front which would cause excessive wear on the front..
