What are the steps to use to command the ABS

Tiny
SHANETAYLOR337
  • MEMBER
  • 2010 FORD FUSION
  • 124,032 MILES
Being stumped by a master cylinder change on the car listed above 3.0. The problem is that I cannot properly bleed system due to ABS module being closed, thus hindering proper repair.I have been reading about using a scanner tool to command comp to open valves to allow proper bleeding. I'm only a parts changer due to my own car dilemmas and I do own a Bosch 1100 diagnostics tool, however i'm not sure if this will be able to fix problem and if so what are the steps to use to command the ABS? I have only used it for code reading and have no clue how to use it in this manner.
Monday, June 1st, 2020 AT 5:44 PM

3 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Have you replaced the HCU/ABS unit? If not, then you do not need to bleed this. The valves are normally closed unless you are in an ABS event. So again, as long as this is not a new unit, it is most likely not the issue.

Did you bench bleed the master cylinder? If not, you have air trapped in the master cylinder. I attached the process on how to bench bleed the master cylinder which you can do installed on the vehicle. Then you will need to bleed the entire system again.

Let me know if this makes sense and we can go from there.
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Monday, June 1st, 2020 AT 6:42 PM
Tiny
SHANETAYLOR337
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  • 14 POSTS
Thanks Kenny, i'm going to slide back on it with my buddy and bench bleed the master cylinder, far as I know, because I am kinda the helper in this situation. All that my buddy has done is remove and replace the master cylinder and upon finishing install we can't get pressure on the brake pedal and having trouble getting fluid to move out the lines. I really appreciate your input and diagrams! I will be back with progress report.
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Monday, June 1st, 2020 AT 8:05 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Sounds great. My guess is it wasn't bench bled. If that is the case, you have air trapped and it can be bled with the brake pedal but it takes forever. Plus they don't want you doing it this way because when you operate the master cylinder dry, it damages the seals. Clearly we don't know if that is the case right now. I would bench bleed it and retest it after you bleed the brakes.

Keep us posted with what you find. Thanks
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Tuesday, June 2nd, 2020 AT 6:25 PM

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