MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: Husy on October 18, 2025, 02:40:08 pm

Title: Golf GTI MK5 - Hissing noise in cabin – disappears when pressing brake pedal
Post by: Husy on October 18, 2025, 02:40:08 pm

Hey folks, looking for a bit of advice. I’m getting a hissing noise inside the cabin, and when I press the brake pedal it disappears. Has anyone experienced this before or know what the common causes or fixes might be? Any advice appreciated!

Title: Re: Golf GTI MK5 - Hissing noise in cabin – disappears when pressing brake pedal
Post by: GVK on October 18, 2025, 03:46:10 pm

Leaking brake servo or brake booster as some call it. Also check the hose from the vacuum  pump on the side of the cylinder head to the servo for cracks and leaks.

Title: Re: Golf GTI MK5 - Hissing noise in cabin – disappears when pressing brake pedal
Post by: ZoliWorks on October 19, 2025, 08:59:34 am

Possibly brake booster hose or pcv to intake hose connections. In my case both were leaking

Title: Re: Golf GTI MK5 - Hissing noise in cabin – disappears when pressing brake pedal
Post by: Husy on October 19, 2025, 10:31:00 am

Would a smoke test be the next best approach here?