Hi, Im hoping that this isnt a serious issue but Im afraid that its bigger than I hoped.

I have a 2010 FX4 F150 with around 46k miles on it. It has been from texas to alaska, alaska to virgina. Being in the military has made me travel around. Today in a parking lot, I went to put my truck into reverse, and I heard a lot pop, like a water bottle being ran over. I immediately put my foot on the brake petal to stop the vehicle, and all i heard was an audible hissing noise, a noise that increased as i pressed on the petal. Once I released my foot from the petal the hissing stopped. Simultaneously, the parking brake light came on, and chirped, as the check brake system flashed on the dashboard. I was able to drive the 3 miles back to my hotel room at which im staying at, and parked it into a parking slot that can be easily assessable by a tow truck if need be. I had to drive slowly, and the only way, that any brake was applied was me pressing as hard as i could with the petal. does anyone have any suggestion before i call a tow service to a shop?

 

F-140 ?

 

Sounds like the vacuum line came off the booster canister under the hood. That's why the hissing sound increased as you applied the brakes. It also could be the booster canister diaphragm ruptured inside housing. Both of these will throw a parking brake light.