My 97 F350 Powerstroke 4x4 brakes are acting funny. When I step on the brakes they will work fine. If I push them again, the peddel is hard as a rock and I can barely get the truck to stop, also the emergency brake light comes on when that happens, and then will go off after a while of driving. Is the problem the vaccume pump on the front of the motor that supplies air to the Power Booster? Please help. This is my 1st diesel..
Thank you
Brandon

 

That would be my guess, before replacing it though, check everything for vacuum leaks. You might have a cracked hose or the grommet at the brake booster might be leaking.