brake pedal fades

2009 DODGE JOURNEY
124,000 MILES • 3.5L • V6 • 2WD • AUTOMATIC
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JBGRANDCHEROKEE
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brake pedal fades but can be pumped up with about two to three pumps. then it holds pressure. master cylinder has been replaced. system has been power and manually bled.
Dec 30, 2017 at 12:01 PM
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CARADIODOC
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Why did the master cylinder need to be replaced? Did you bench-bleed the new one? Does the vehicle have anti-lock brake?
Dec 30, 2017 at 2:31 PM
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JBGRANDCHEROKEE
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felt like a master cylinder bypass. hard to isolate from ABS hydraulic module and yes it was bench bled. pedal feels about 25 % better. pumps up faster now.my question is would the ABS module bypass that easily?
Dec 31, 2017 at 10:47 AM
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JBGRANDCHEROKEE
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I have only had experience with Ford frame mounted ABS units failing and they are relatively easy to test.
Dec 31, 2017 at 10:49 AM
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STRAILER
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Yes what happens is the ABS unit traps the air inside of it. You must connect and ABS scanner and work the valves while bleeding the system.

Here are guides to help you get an idea of what it will take to fix it. Make sure your scanner can test the valves before you get one or have a shop do it.

https://youtu.be/rTtAnsOlZU4

and

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

and

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Please let us know what you find. We are interested to see what it is.

Cheers, Ken
Jan 2, 2018 at 11:37 AM