Replaced Master cylinder and pedal still going all the way to the floor

Tiny
JOBRAIRA
  • MEMBER
  • 2010 FORD FUSION
  • 2.5L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
I have installed a master cylinder to my car. I have purged it before installing it. The brake pedal continues to go all the way to the floor when I press it. I tried to purge from the wheels with the help of a person who pumped three times the pedal but I open the port for purge and no fluid. I tried several times and continue dry. I think this car has ABS. Can be that the fluid does not go to the calipers because I have to purge the ABS? And how do I do that?
Monday, July 8th, 2019 AT 10:55 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

You need a scan tool that can perform the automated bleeding procedure for the ABS hydraulic unit. You have air trapped in the unit.

Roy

Hydraulic Control Unit (HCU) Bleeding

WARNING: Do not use any fluid other than clean brake fluid meeting manufacturer's specification. Additionally, do not use brake fluid that has been previously drained. Following these instructions will help prevent system contamination, brake component damage and the risk of serious personal injury.

WARNING: Carefully read cautionary information on product label. For EMERGENCY MEDICAL INFORMATION seek medical advice. In the USA or Canada on Ford/Motorcraft products call: 1-800-959-3673. For additional information, consult the product Material Safety Data Sheet (MSDS) if available. Failure to follow these instructions may result in serious personal injury.

WARNING: Do not allow the brake master cylinder to run dry during the bleeding operation. Master cylinder may be damaged if operated without fluid, resulting in degraded braking performance. Failure to follow this instruction may result in serious personal injury.

NOTICE: Do not spill brake fluid on painted or plastic surfaces or damage to the surface may occur. If brake fluid is spilled onto a painted or plastic surface, immediately wash the surface with water.

NOTE: When any part of the hydraulic system is disconnected for repair or installation of new components, air can get into the system and cause spongy brake pedal action. This requires bleeding of the hydraulic system after it is correctly connected.

All vehicles

1. Use the Pressure Bleeding procedure to bleed the system. For additional information, refer to Brake System Bleeding.

2. Connect the scan tool and follow the ABS HCU Hydraulic Control Unit (HCU) bleeding instructions.

3. Repeat the Pressure Bleeding procedure to bleed the system.
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Tuesday, July 9th, 2019 AT 2:21 AM
Tiny
JOBRAIRA
  • MEMBER
  • 4 POSTS
But how can I know exactly that the ABS is the problem?
Always happen like this.
Can I just open the calipers bleeders until I get fluid coming out?
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Tuesday, July 9th, 2019 AT 9:58 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Air gets into the ABS unit from the replacement of the master.

No, opening the bleeders does not bleed the ABS. It must be done with a scan tool.

Roy
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Tuesday, July 9th, 2019 AT 10:01 AM
Tiny
JOBRAIRA
  • MEMBER
  • 4 POSTS
Now, I mentioned the ABS but I'm not sure is that is the problem.
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Tuesday, July 9th, 2019 AT 1:31 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You need to start there and bleed the ABS with the procedure I sent you.

Roy
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Tuesday, July 9th, 2019 AT 1:36 PM

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