When I first start my 2012 F-150 my brakes are hard, almost like pushing metal on metal If I back up and use them they sometimes will grind. If I sit for a minute or rev the engine, they work like normal. Only notice this first thing in the morning or after the truck has sat for a long time. Not sure how the system works, but it seems like it is taking sometime to fill a hydraulic reservoir. Once this is over the brakes work fine.

 

The system does not work that way. Which model F150? Which engine?
There have been problems with the Ecoboost and the 5.0L brakes reported on the forum. You might try searching.

 

If you have a 5.0, the master cylinder uses engine vacuum to boost the brakes. I don't see why you would have any wait for the brakes to charge, mine does so instantaneously as soon as I start the engine. The ecoboost uses a vacuum pump since you loose vacuum under turbo boost. Not sure if it uses engine vacuum when not in boost or not, but it seems weird you aren't getting any brake boost during idle.

If you do have the ecoboost, I know there is a recall on the brake booster system. I don't know much about it since I have a 5.0, so see this link for more info. It might be applicable to you:

https://www.f150forum.com/f38/electr...-15n05-332618/

 

It's has a 6.2 Ecoboost. I have around 75000 miles, started a few months ago. I took it in for the recall, so that was done. I am wondering if the new part isn't as bad as the original.

 

Dare i say Unicorn!!??

 

Motor doesn't exist... Unless you put twin turbos on the 6.2L in that case SAWEET!

I love my 6.2, but add 2 turbos and that would be a crazy sweet motor...

So do you have the 6.2 L V8 or do you have the 3.5 L ecoboost V6?

 

Its the 6.2 twin turbo, platinum.

 

Umm I don't think so. I could be wrong, but I have never heard of that.

You probably just have the 6.2L V8 , which is what I have. And it is not turbo. Just a big sweet motor.

 

Do you have pics under the hood?
It is probably 3.5L Ecoboost or 6.2L.

 

He probably has the 3.5. The reason I say this is I believe they had a problem or recall for the brake booster.