960 1997 hissy brakes

timv · Post by **timv** » 18 Aug 2009, 07:26

Hi Volvo folk.
Can anyone help me with this problem? When I apply the brakes to my 960 there is a hissing sound like air escaping at a regular pace. The brakes actually do work when I touch them lightly but only when I apply full force and come to a stop does the hissing sound stop.

thanks.

Post by **billofdurham** » 18 Aug 2009, 11:52

Welcome to Matthew's Volvo Site.

The brake booster (servo) always makes a hissing noise when you brake as it works on a vacuum system. Usually when you are travelling the noise isn't noticeable.

For a detailed description of how it works (with moving pictures - just click on "braking mode" under the picture) see brake servo.

I would suggest you check for a vacuum leak at the booster.

Bill.

timv · Post by **timv** » 18 Aug 2009, 13:17

thanks Bill.