ABS brake pedal sinking towards floor

2009 JEEP CHEROKEE
133,000 MILES • 2.8L • 4 CYL • 4WD • AUTOMATIC
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GEOFFREY ETHELSTON
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  • 3 POSTS
Hi, problem with brake pedal sinking with engine running solid with engine off. Have bled about a gallon of fluid with and without scanner clean fluid. no leaks, all hoses good. When driving vehicle stops perfect but if you put extra pressure on the pedal it sinks slowly. I have ordered a master cylinder just in case. I live in Ireland and this is the only Jeep Cherokee KK, and help from dealers does not exist only want to sell new. When i bled the vehicle it was done to factory spec manually as per instructions with scanner. Help. Thanks
Aug 24, 2021 at 12:01 PM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Hi,

If the pedal slowly goes to the floor when holding pressure on it, chances are the internal plungers are bad and allowing fluid to bypass. Take a look through this link.

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

If you determine it is the master cylinder, and it does sound like it, here is a link that shows in general how it's done:

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

The attached pics are specific to this vehicle (not sure if you have a right or left-hand drive).

Let me know if there is something I can do to help. Also, there were no 4 cylinder engines offered in this vehicle, so let me know which engine you have.

Take care,

Joe

See pic below.
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Aug 24, 2021 at 8:54 PM
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GEOFFREY ETHELSTON
  • MEMBER
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Hi and thanks for your reply. if you check my statement you will see i live in Ireland and the Jeep is fitted with a VM 2.8 Turbo Diesel. I have a master cylinder ordered and will fit when it arrives. Thanks again, Geoff
Aug 24, 2021 at 11:47 PM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Hi,

Okay, that makes sense. Let me know if that takes care of the problem.

Take care,

Joe
Aug 25, 2021 at 5:12 PM
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GEOFFREY ETHELSTON
  • MEMBER
  • 3 POSTS
Hi Joe, thanks for your help. All the best.
Aug 26, 2021 at 12:36 AM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
You are very welcome. Let me know if I can help. Also, if you have a chance, let me know if this takes care of the problem.

Take care,

Joe
Aug 26, 2021 at 8:09 PM