seeuuaye08 Report post Posted August 13, 2017 I have a 2008 Ford Edge Limited 2WD that recently showed obvious signs of a failed brake booster (i.e. hard brake pedal, no give when engine starts and foot is on the pedal, hissing sound/vacuum leak when brake pedal is pushed). I removed the brake booster and went up to the parts department at my local Ford dealership to get an OEM Motorcraft brake booster. Installed the new brake booster, put everything back together, bled the master cylinder of air and now there is no resistance in the pedal AT ALL. Pumping the brakes does nothing and if you hold down the pedal to the floor there is a noticeably louder hiss coming from near the pedal where the booster arm connects to the brake pedal. The engine will also drop in idle if you hold the pedal down indicating to me a vacuum leak. I'm positive everything is hooked back up correctly and there is no other vacuum leak in the engine bay because the hissing is only heard in the cabin when I press the brake pedal down. Has anyone had this problem with a new Motorcraft brake booster? Is it possible there is something else I'm missing? Will the dealership let me exchange the new, failed brake booster for another one? It did say on the receipt that returned parts must not have been installed but how are you supposed to test a brake booster without installing it first? Share this post Link to post Share on other sites
fishx65 Report post Posted August 13, 2017 Just to add to your thread, isn't there a simple test to check for a failing booster? My 2011 is starting to hiss a little louder. Share this post Link to post Share on other sites
seeuuaye08 Report post Posted August 13, 2017 (edited) Just to add to your thread, isn't there a simple test to check for a failing booster? My 2011 is starting to hiss a little louder. There may be a way to if you rig up a vacuum pump, some hose and a spare check valve but I don't have those lying around. Edited August 13, 2017 by seeuuaye08 Share this post Link to post Share on other sites
akirby Report post Posted August 13, 2017 If it's really defective they will exchange it but first you really need to rule out the installation. I know you said it was installed correctly but I've said that a lot of times and been wrong. 1 Share this post Link to post Share on other sites
enigma-2 Report post Posted August 13, 2017 Inasmuch as the booster has a 150,000 extended warranty why not have the dealer do it. (Btw, has the diaphragm starts to tear, the booster starts hissing, pedal get spongy. Only gets worst, might as well have it changed). 1 Share this post Link to post Share on other sites
fishx65 Report post Posted August 18, 2017 Inasmuch as the booster has a 150,000 extended warranty why not have the dealer do it. (Btw, has the diaphragm starts to tear, the booster starts hissing, pedal get spongy. Only gets worst, might as well have it changed). Just had the booster replaced today in my 2011 at 95,000 miles. Brakes were still functioning fine but that snake under the dash was getting louder and louder. The hissing is definitely a dead giveaway cuz the new booster is completely silent. 1 Share this post Link to post Share on other sites
Mgavin1985 Report post Posted September 7, 2017 Brake booster fail today heard distinctive sound it really is a hiss. I had brakes engaged coming Down slight incline from 45 mph to 4 way stop sign engage %25 heard hissing and had loss of vacuum had to pump brakes I was able to get brakes to work by pumping. Off to dealer under extend warranty and Ford road side assistance gave free tow. If it was significant other would have blown stop sign and cut trees in half at that speed. Share this post Link to post Share on other sites
WWWPerfA_ZN0W Report post Posted September 7, 2017 Wow, glad u made it out ok. Share this post Link to post Share on other sites
