Brake pedal

2007 LINCOLN MKX
133,691 MILES • 3.5L • V6 • 4WD • AUTOMATIC
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HUGGIEBEAR312
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  • 25 POSTS
Brake pedal gets hard to press sometimes. I took it to have an oil change they check the brakes and now my brake pedal is hard to press. it does not happen all the time just sometimes. I have checked the brake fluid and it is fine. what would cause this?
Dec 6, 2017 at 7:06 AM
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JACOBANDNICKOLAS
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Since it only happens at times, it may be vacuum related. The brake power assist booster may be losing vacuum or there may be a leak in the system. Watch this guide on how to find vacuum leaks. If there are no leaks, I would recommend testing the booster itself to see if it will hold vacuum.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
Dec 6, 2017 at 7:56 PM
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HUGGIEBEAR312
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Thank you. I am also hearing a hissing noise when I am pressing on the brake.
Dec 7, 2017 at 7:57 AM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Most likely it is the booster. Check to see if it will hold vacuum.
Dec 7, 2017 at 6:07 PM
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HUGGIEBEAR312
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Okay, will check the booster and get back with you.
Dec 7, 2017 at 10:34 PM