There are two common problems that produce this noise. The most common cause here in the high desert is the presence of a rattlesnake under the dash. They react to the proximity of your foot by rattling (sounds very much like hissing) when you press on the brake pedal. This means that you will need to entice the snake to leave the premises before you drive the car again, or else be sure to wear a good set of leather boots when you drive. If you live elsewhere, the problem is most likely an air leak in the brake booster. This means that you need a new brake booster, available at almost any auto parts store. It is an easy job to change it, if you just pay attention to how things are put together when you take the old one out. All things considered, it is probably easier than curing the first problem. Dick Benjamin -----Original Message----- Jeffrey M. Fastov Sent: Wednesday, August 25, 2004 6:28 PM To: mailing-list@xxxxxxxxxxxxxxxx Subject: Re: IML:68 brakes my brakes hiss when i step on them.mc full.is it the booster or any other suggestions.thanks