Answer
Aug 24, 2025 - 09:48 AM
That hissing sound you're hearing when pressing the brake pedal on your Nissan Murano is most likely coming from a leaking brake booster — specifically, a vacuum leak in the booster or the vacuum hose connected to it.
The brake booster uses engine vacuum to help make braking easier. When there’s a leak in the diaphragm or the check valve, you'll often hear a hissing sound (especially when pressing the brake pedal), and the pedal might start feeling harder to press than usual. That hissing is vacuum escaping — kind of like a tiny air leak — and it gets more noticeable when you hit the brakes because that's when the system is active.
What you can check:
- With the engine running, press and hold the brake pedal — if the hissing gets louder the more you press, that's a strong sign it’s the brake booster.
- Try lightly pumping the pedal with the engine off, then hold it down and start the engine — if the pedal doesn’t slightly drop or the feel doesn’t change, the booster isn’t working right.
If that's the case, the booster or the vacuum hose needs to be replaced. It's not typically a DIY job unless you're confident with brake systems, but a good repair manual (like the one in our listing) can walk you through the steps if you want to check it yourself.
Perhaps if you could let us know more about your Murano, we can help you find the perfect manual for your needs here.
