Brake pedal is spongy (all the way down when engine is running)?

Tiny
ELIESER PEñA REYES
  • MEMBER
  • 2008 MERCURY MARINER
  • 2.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
I replaced the calipers and bled the brakes, the car brakes well when I press the pedal two times. But if I wait a few seconds, the pedal goes all the way down. With the car running.
The ABS pump was working fine before replacing the calipers.
Sunday, October 30th, 2022 AT 8:21 PM

5 Replies

Tiny
SQM
  • MECHANIC
  • 6,383 POSTS
Hello,

This vehicle does require a scan tool to properly bleed the ABS.
The scanner allows you to open the ABS valves and have a proper bleeding process.

Here is a helpful guide:

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

I have attached the procedure below for your reference.

Let me know if you have any questions.
Thank you.
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Sunday, October 30th, 2022 AT 9:20 PM
Tiny
ELIESER PEñA REYES
  • MEMBER
  • 3 POSTS
We already use the scanner to run an OBDII controlled bleeding process. I've already did it two times, and it's still not working properly.
Is it possible that the HCU is damaged? Somehow the pressure releasing valve went all the way always open?
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Sunday, October 30th, 2022 AT 9:38 PM
Tiny
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  • MECHANIC
  • 6,383 POSTS
Are you getting any ABS error codes? Typically is the module is bad it will throw code.
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Tuesday, November 1st, 2022 AT 10:25 PM
Tiny
ELIESER PEñA REYES
  • MEMBER
  • 3 POSTS
No error codes. Looks like the HCU. Replaced the ABS HCU and is working fine now.
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Wednesday, November 2nd, 2022 AT 4:30 AM
Tiny
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  • MECHANIC
  • 6,383 POSTS
So, you were able to fix it. That is great news.
Thank you for updating us.
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Friday, November 4th, 2022 AT 5:47 PM

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