[arex]

I have a 2005 AC Tundra that started something last week. There's a faint, but extremely high-pitched, whistling sound (almost like tinnitus) inside the cab when the engine is running. It took a couple days to narrow down, but I've connected it to the brakes. If I press the brake pedal more than half an inch, the whistling stops, and within that 1/2-inch of travel, I can make the whistling change pitch, so the sound is mechanical, not electrical, like some electronics fixing to fail.

I'm assuming that it's a vacuum leak in the brake booster canister. THe brakes are, for now, working just fine. It's not audible within the engine compartment, only the cab. The question is, would this be a whole canister replacement thing, or is there simply a seal that can be replaced?

 

[Is-rider]

I have a 2005 AC Tundra that started something last week. There's a faint, but extremely high-pitched, whistling sound (almost like tinnitus) inside the cab when the engine is running. It took a couple days to narrow down, but I've connected it to the brakes. If I press the brake pedal more than half an inch, the whistling stops, and within that 1/2-inch of travel, I can make the whistling change pitch, so the sound is mechanical, not electrical, like some electronics fixing to fail.
I'm assuming that it's a vacuum leak in the brake booster canister. THe brakes are, for now, working just fine. It's not audible within the engine compartment, only the cab. The question is, would this be a whole canister replacement thing, or is there simply a seal that can be replaced?

My truck has been doing the exact same thing!!!... I've been searching high and low for some info on what is making this noise. Hopefully someone can shed some light on this, cuz it's driving me batty!!???

 

[UPbuilder]

Disconnect the vacuum line from the booster, plug it, and see if the noise goes away.

 

[arex]

Disconnect the vacuum line from the booster, plug it, and see if the noise goes away.

It does. I'm thinking there's a seal where the pushrod goes into the canister, but I've never worked on a booster canister, so I only have a vague idea of what the internals are like.

 

[Togman]

Any update to this?

 

[chrisguy]

Following. I haven't tried pushing the brakes while I hear it but it has a direct correlation with engine RPM

 

[Is-rider]

Bump.
The high pitch whistle seams to go away in the cooler temps. Spring is here and its back. I think it may be linked to the brake booster. Any help would be greatly appreciated.


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[Rrumbler]

A leak in the diaphragm in the booster.

 

[Is-rider]

A leak in the diaphragm in the booster.

Thank you ?


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[bstrom]

Hmmm, I've also got a faint high pitch whine but it only comes up with light acceleration at 65-75 highway speeds - letting off the accelerator pedal during typical deceleration or acceleration changes and it goes away - nothing to do with brakes operation. Doesn't even occur at lower street speeds. No issues with alternator according to my Innova 12V cigarette lighter LED meter. Different situation?

 

[Is-rider]

It sounds like a totally different high-pitched whine. The high-pitched noise changes its tone when I put my foot on the brake pedal, the whine also continues when I shut the truck off you can still hear it for 20 to 30 seconds.


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[arex]

UPDATE - A brake booster replacement fixed the whistling.

 

[Billy Wilson]

I have a 2005 AC Tundra that started something last week. There's a faint, but extremely high-pitched, whistling sound (almost like tinnitus) inside the cab when the engine is running. It took a couple days to narrow down, but I've connected it to the brakes. If I press the brake pedal more than half an inch, the whistling stops, and within that 1/2-inch of travel, I can make the whistling change pitch, so the sound is mechanical, not electrical, like some electronics fixing to fail.

I'm assuming that it's a vacuum leak in the brake booster canister. THe brakes are, for now, working just fine. It's not audible within the engine compartment, only the cab. The question is, would this be a whole canister replacement thing, or is there simply a seal that can be replaced?
[/QUO
I have had the whistling noise for a while on my 2011 Tundra. I discovered that my pcv valve was stopped up. I replaced it and the whistle noise has gone away!

 

[Billy Wilson]

I have had the whistling noise on my 2011 Tundra for a while now. Couldnt figure it out . Discovered that my pcv valve was stopped up. I replaced it and now the whistle noise is gone.