Yahoo Answers is shutting down on 4 May 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Hissing coming from brake?

I'm not sure if this hissing noise is a sign of a bad brake booster, master cylinder or vacuum hose. My brake system works fine even since the hissing started. The brake pedal isn't tensing up on me and I'm not flooring it out either. The hissing stops when I press the brake all the way down, but hisses non stop while driving. Any ideas on what I should replace? I'd hate to replace the brake booster just to find out it's a totally different issue.

6 Answers

Relevance
  • 6 days ago

    IT is BRAKE BOOSTER, Remove the VACUUM to it and then SUCK on it! OPEN THE HOOD otherwsie and LISTEN for  the LEAK SOUND! NO CAR TYPE mentioned here! GOOD LUCK!!HTIS haapesn MOSTLY frmousing OIL that evetuanlly EATS UP RUBBER PARTS like DIAPHRAGMS! THANK GOD for REAL SYNTHETIC lilke PENNZOIL ULTRA PLATINIUM! It wil NOT rot RUBBER or ruind GASKETS AND SELAS like Valvoline WILL DO! I SUED THEM and I WON! I also sued CASTROL an won there TOO! BYE NOW

  • Anonymous
    7 days ago

    Troubleshoot.  Get a smoke machine and leak check the brake booster and vacuum hose.

  • 7 days ago

    Likely just a cracked hose

  • 7 days ago

    The brake booster has sprung a leak somewhere. And the hissing you here is that it's sucking air from somewhere. Find out where it's sucking air from. I need yourself up some of that two-part fuel tank repair putty and shove it in the hole. It's not pressurized it's a vacuum leak you can safely stop it. Just find the vacuum leak

  • 1 week ago

    If you have a stethoscope (or a piece of hose of appropriate length) you should be able to narrow down exactly where the hissing (vacuum leak) is coming from.  It probably is the brake booster , but it will be better to know for sure, by locating the source. 

  • Anonymous
    1 week ago

    A family of snakes have probably just made themselves a gone somewhere with your car’s chassis.

Still have questions? Get answers by asking now.