# Whistling noise

**URL:** <https://community.cartalk.com/t/whistling-noise/38215>\
**Category:** Maintenance/Repairs\
**Tags:** fx35, infiniti\
**Created:** [October 17, 2009, 1:16pm UTC](https://community.cartalk.com/t/whistling-noise/38215 "2009-10-17T13:16:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![oleteeth](https://avatars.discourse-cdn.com/v4/letter/o/59ef9b/32.png) [@oleteeth](https://community.cartalk.com/u/oleteeth)\
**Post date:** [October 17, 2009, 1:16pm UTC](https://community.cartalk.com/t/whistling-noise/38215/1 "2009-10-17T13:16:41Z")

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I get a whistling (not squeaking)noise when I step on my brakes at above 40 MPH. The noise is very low , if at all below that. Is that a leak in the master cylinder, etc?  
  
 Thanks

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [October 17, 2009, 4:29pm UTC](https://community.cartalk.com/t/whistling-noise/38215/2 "2009-10-17T16:29:14Z")

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Not the master cylinder, but a leak in the vacuum brake booster or the brake booster check valve. Those should be checked out first.

Tester

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**Author:** ![oleteeth](https://avatars.discourse-cdn.com/v4/letter/o/59ef9b/32.png) [@oleteeth](https://community.cartalk.com/u/oleteeth)\
**Post date:** [October 17, 2009, 6:18pm UTC](https://community.cartalk.com/t/whistling-noise/38215/3 "2009-10-17T18:18:39Z")

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Thanks. I will check that out.