Truck
04 2WD STX
4.6 L
100,000 miles but has done it for the past 15,000 when it is warm.


I have searched but found nothing on this...

When its warm out 80+ degrees the brake pedal sticks at the resting position.

To explain it a little better - When I jump in the truck and hit the pedal for the first time there is a resistance when the pedal first starts to move. It is fine for the next couple uses but returns if I travel without hitting the brakes for some time. Travel 10-15 miles hit brakes again and resistance when I hit the pedal, not a smooth action. Braking is not effected just feel of the pedal for the first 1/2-1" of travel, after the 1" the pedal is fine.
One thing I have noticed it only does it when it is warm, over the winter the issue went away but has returned with the warm weather, maybe a seal or joint expanding?

Not sure where to start and no help from a search.. booster, master, clean the caliper action.

 

the first thing I would look at is the pedal linkages

if thats not it, it could be a bad booster... nothing you can fix there, you would need to replace it

 

OK just got done checking and lubing the pedal linkage. Not much under there, pedal mounts to bracket and the rod that goes into the booster. Lubed all the points with white Teflon spray but have a feeling thats not going to take care of it.

Booster does not look bad to replace 6 bolts and out.

Still open to any other suggestions or if anyone has had this happen.

 

Im having the exact same issue on my 07 f150 and cant find any help. Did u figure out what causes this issue? Help!