Brake Pedal Hard As Rock At Start ('14 Laramie 4x4)

[Curtamous]

Recently purchased this '14 Laramie 4x4 Hemi
Occasionally, when I get in to start the truck, when I press brake as required to start the truck, the brake pedal is hard as a rock.
When this occurs it doesn't acknowledge my button press either. I must release button and push a time or two more for it to crank-up. Don't know if the two issues are related or not..

Anybody have a clue?

Thx in Adance!

 

[Nicholas Cove]

Your brake booster is leaking need a new one. Possibly check valve.

 

[bigdodge]

Mine does this. Changed the check valve and still does it. Doesn't seem to cause any issues driving so I haven't tried changing the booster.

 

[Jeepwalker]

Does the pedal go down right after the truck is started? (the booster receiving engine vaccum)

 

[Elvira]

Driving it daily, the brake pedal should not go hard on you unless the booster, check valve or hose is leaking down. I know it will go hard from sitting a couple of days or so, vaccuum will leak regardless. If that is the case after a few days, then not to worry. Leaking vaccuum when running may even cause your truck to run lean, in which case the computer will compensate, that will be noticeable in fuel consumption.