Brake pedal fades

Tiny
JBGRANDCHEROKEE
  • MEMBER
  • 2009 DODGE JOURNEY
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 124,000 MILES
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.
Saturday, December 30th, 2017 AT 12:01 PM

4 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,752 POSTS
Why did the master cylinder need to be replaced? Did you bench-bleed the new one? Does the vehicle have anti-lock brake?
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Saturday, December 30th, 2017 AT 2:31 PM
Tiny
JBGRANDCHEROKEE
  • MEMBER
  • 3 POSTS
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?
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Sunday, December 31st, 2017 AT 10:47 AM
Tiny
JBGRANDCHEROKEE
  • MEMBER
  • 3 POSTS
I have only had experience with Ford frame mounted ABS units failing and they are relatively easy to test.
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Sunday, December 31st, 2017 AT 10:49 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,973 POSTS
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
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Tuesday, January 2nd, 2018 AT 11:37 AM

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