take my foot off the gas and hit the brakes I hear a hissing noise

Hi,

Replacing the booster isn't too hard. You will have to remove the brake master cylinder to access it. The worst part of the job is unbolting it from the firewall, It is one from the inside of the vehicle up under the dash.

If you look at the attachments below, I included the directions and the pics specific to your vehicle for replacement. However, there are two possibilities. First, if you have ABS, the procedure is different than if your vehicle doesn't have ABS. I will include the directions for both systems. First will be with ABS. Non-ABS starts at pic 18.

I hope this helps. Let me know if you have other questions.

Take care,

Joe

See pics below