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Brake Hissing proof of concept fix

Discussion in '5th Gen 4Runners (2010+)' started by Checook, Oct 27, 2018.

  1. Oct 27, 2018 at 1:43 AM
    #1
    Checook

    Checook [OP] New Member

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    So, you can't replace a part and make the hiss go away. I wanted to see if insulation would help. I got some foam and encapsulated the braking mechanism being careful to not touch the moving rod or spring on top or the pedal stem. It did reduce the sound considerably. If someone made a two piece clamshell of injected plastic with insulation that could do this I think it would be a "shut up and take my money" item. It might also be possible to make a cone/tube of foam that covers the bubber boot and brake rod that could block sound without hindering function, basically getting right to the source. Thoughts or ideas?IMG_20181027_013201.jpg
     
  2. Oct 27, 2018 at 7:24 AM
    #2
    j cat

    j cat New Member

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    spacer lift front 1inch
    typical hiss noise can be the booster has a vacuum leak . did this suddenly occur ?

    another reason maybe the rod is rubbing on some other component..

    with vehicle off tranny in neutral foot on brake .. how many times will the brakes work as you work the brake pedal ..
    should work 3 or more times engine off.. booster holds vacuum..

    another test park vehicle for a few hours do not start engine , put tranny in neutral the brakes should work if not then a leak in the booster vacuum system..
     
  3. Oct 27, 2018 at 11:07 AM
    #3
    Checook

    Checook [OP] New Member

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    It is a "normal" sound. Most people just turn the radio up. I have misophonia, so it drives me nuts.
     
  4. Oct 27, 2018 at 12:29 PM
    #4
    j cat

    j cat New Member

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    spacer lift front 1inch
    2015 model so go to dealership and take a ride in a new runner see if you have the same hiss volume ..

    some have had this hiss .. if it is a leak the brake pedal will be harder to push down over time.
     
  5. Oct 27, 2018 at 2:35 PM
    #5
    rkwfxd

    rkwfxd New Member

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    I'm lucky. I am losing my hearing so even if it is hissing I can't hear it. : -)
     
    jester243, j cat and Checook [OP] like this.
  6. May 13, 2019 at 1:23 PM
    #6
    Checook

    Checook [OP] New Member

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    It persists in neutral. I verified that nothing is rubbing. The sound is like a minor air leak squishing past a wet o-ring.....only way I can describe it. When I shut the truck off and slowly depress the brake it persists for around 7 or 8 presses. I wonder how difficult it would be to replace the unit entirely?
     
  7. May 13, 2019 at 6:22 PM
    #7
    CommTech16

    CommTech16 New Member

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    2019 brand new with 20miles does it, 300miles in and still makes the noise. I'm not concerned about i .
     
  8. May 13, 2019 at 11:55 PM
    #8
    Checook

    Checook [OP] New Member

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    I wish I could ignore it but I have misophonia. When I hear odd noises it locks in my attention and drives me nuts.
     
  9. May 14, 2019 at 5:25 AM
    #9
    CommTech16

    CommTech16 New Member

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    I have a slight thump in the rear and it's got my full attention right now. 328mi on the odo
     
  10. May 14, 2019 at 11:27 AM
    #10
    Checook

    Checook [OP] New Member

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    I had a thump in the rear of my 09 Tacoma years ago when I went over speed bumps. I put a cheap camera on a magnet, attached it in every conceivable angle one at a time and went over a speed bump, edited the footage to play each event two seconds before and after in one long video and watched in repeat until I realized the leaf spring bushing was binding.
     

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