Hi - I have a 96 F150 - just installed a new master cylinder and bled all brakes - however my brake pedal makes a swoosh sound and is not firm. The calipers were replaced a year ago / checked rear wheel cylinders - no leaks. The brake shoes on front are new and the rear too. Is the booster bad causing pedal problem?

 

The Brake Booster has a leaking diaphragm inside and will have to be replaced.

 

Thank You - I wasn't sure - I have owned this truck since new

 

Also, changin the front rubber brake lines will give you a firmer pedal as well....especially the braided bake lines....definitely worth the money.