Hey guys. My 97 F-150 (4.6 L) has developed what sounds like a vacuum leak under the driver's side dash somewhere above the pedals. I can't see anything obvious. It changes sound with various positions of the brake pedal, and I can make it stop with hard acceleration for a few seconds. The brake pedal feels the same. I'm assuming the problem is probably my brake booster, right? Or should I be looking elsewhere? If so, how hard is it to replace?

 

Brake booster tests
I replaced the one in my 1983 F250 after many years of use. It was easy.

 

Sounds like the booster . Not hard to replace . Block off the vac line to the booster , if noise goes away , bad booster . If no change , look further . 2 bolts on master cyl and 4 bolts holding booster to firewall . Brake rod to peddle assy clip . Easy job .

 

Thanks guys! This truck holds a sentimental value to me. It got me through some rough times for a very long time. It's still my daily driver.