GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 4 of 4

Thread: Hissing noise?

  1. #1
    Sr. Apprentice big bopper's Avatar
    Join Date
    May 2010
    Location
    Nottinghamshire, England
    Posts
    37

    Default Hissing noise?

    1994 5.7 Vandura

    ok ever since i have had a top end re-build on my engine my cruise control has stopped working and i now have a hiss when ever i put my foot on the brake pedal, i dont have a servo (i think what i have is called hydroboost?) so its not that, i have been told the hissing is possibly somthing to do with the cruise control which is why the cruise control is not working?

    can any one tell me definatley what the problem is? and more importantley how to rectify it?

    thank you Tony

  2. #2

    Default

    Hissing is generally a vacuum leak. It sounds like you might have a bad brake booster; look at your master cylinder, there should be a vacuum line connection somewhere close by it, make sure that line is good.

    As far as your cruise, I'm not sure if that year used a vacuum driven cruise or electronic. If it's electronic, it's possible they didn't get a harness reconnected correctly. I would have to guess it's electronic, and that the hissing you hear is unrelated to the cruise problem.

    Hopefully someone with more experience on this vehicle can chime in.
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

  3. #3
    Sr. Apprentice big bopper's Avatar
    Join Date
    May 2010
    Location
    Nottinghamshire, England
    Posts
    37

    Default

    my van doesnt have the brake servo its got the hydroboost, so it's not the brake booster, it seems to be leaking air/ hissing from just above the brake pedal

  4. #4

    Default

    ahhh ok gotcha. I wasn't familiar with the hydroboost but understand it now.

    The hissing is only happening when you press the brake though correct? To me that means it's something related to the brake/hydroboost system. If you have no leaks and brakes feel good, then I would think the noise isn't a problem, other than being annoying. If you're worried about it, check with the company (this should be the correct link: http://www.hydratechbraking.com/)

    At any rate, The hissing should not be related to your cruise problem. if you had a constant hissing, then that could be a vacuum leak which (if your cruise is vacuum driven) could cause a problem with cruise. My guess is more that your cruise system is all electric, and you have a loose connection somewhere in the cruise setup. Double check all your wiring on the engine, make sure everything is plugged in well and the cruise control unit is properly connected to the throttle body.
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

Similar Threads

  1. Excessive Cab Noise - 2010 Chevy Silverado & 2010 GMC Sierra Road Noise
    By Hawgin1 in forum Chevy Silverado Forum (GMC Sierra)
    Replies: 399
    Last Post: 12-02-2013, 12:34 PM
  2. 2006 silverado 5.3L hissing noise when reving
    By Jimbo3 in forum General Chevy & GM Tech Questions
    Replies: 14
    Last Post: 02-02-2011, 09:07 PM
  3. Fan Noise
    By Skyblue in forum Chevy Trailblazer Forum (GMC Envoy)
    Replies: 1
    Last Post: 05-10-2009, 08:31 AM
  4. What was that noise?
    By jaywbeeman in forum Chevy Suburban Forum (GMC Yukon XL)
    Replies: 1
    Last Post: 11-16-2007, 11:09 PM
  5. Noise
    By kknobl in forum Chevy Suburban Forum (GMC Yukon XL)
    Replies: 8
    Last Post: 07-03-2007, 11:14 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •