Hi I'm looking to see of any one can help. My car (Volvo v40 Rdisgin 2015) has been making a noise that sort of sounds like a relise of air I think its comming from the front drivers side. The sound is more noticable when I go over a bump or pot hole or when I take my foot off the accelerator. I've since then taken it to two garages the one told me ot was the gears in the air conditioning and they would not be able to do that kind of job the second a Volvo Specialist told me it was the rear brake disc backing plates. They removed them and told me the problem was solved. Unfortunately it's still hissing at me. Anyone have any ideas of what the sound could be? Thanks.