Brakes will not hold pressure

Tiny
BIGED2021
  • MEMBER
  • 2005 DODGE DAKOTA
  • 4.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 129,527 MILES
Brakes will not hold pressure. We have bled them more then once, we have bled the master cylinder and they still go to the floor. What's wrong?
Tuesday, July 6th, 2021 AT 7:49 PM

6 Replies

Tiny
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  • MECHANIC
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Hello,

It sounds like you might have a defective brake master cylinder. This is a helpful video of bleeding the brake system:

https://youtu.be/w7gUsj2us0U

You might also want to make sure there is no air in the ABS system control valve. This video will help

https://youtu.be/nQRnKyVyMuQ

Check out the images (Below). Please let us know how it goes
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Wednesday, July 7th, 2021 AT 9:09 AM
Tiny
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Hello,

This is a good article that you might find helpful:

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

Thank you.
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Friday, July 9th, 2021 AT 10:42 AM
Tiny
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It has a new master cylinder, new brake booster which I put on it myself. When they brung the truck to me they had already put the new calipers and the new brake lines (which are copper lines) on it.
With the engine off the brakes will pump up. As soon as I start the engine and push the brake it goes to the floor. I can pump them up singing running or not that's it. I've bleed all the lines multiple times I've bleed the master cylinder multiple times. I do not have a scan tool that will bleed the abs and e eve. If I did I couldnt use it on this truck. Because where you hook up the scan tool at it has been tore up wires cut and everything idk what all that is about didnt ask didnt care. So I need a way around that. Or I need to know if I can just by pass the abs and if so how.
And just here in the last little bit I've tried bleeding all the brakes again only to notice that I'm not getting any fluid coming out when bleeding the back brakes on either side. I've never had this problem and a vehicle and I really need to get this finished and out of here.
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Friday, July 9th, 2021 AT 11:36 PM
Tiny
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Hello,

Have you got a chance to check the brake booster on that vehicle?
Many times the booster will case the brake pedal to go to the floor as well.

https://youtu.be/aiIvBVsiczY

Please let me know.
Thank you.
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Sunday, July 11th, 2021 AT 9:02 PM
Tiny
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I put a brand new booster on it and still nothing.
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Monday, July 12th, 2021 AT 6:28 AM
Tiny
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This is surely a tricky one. Did you make any progress with this truck. Have you done any other procedures?
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Wednesday, July 14th, 2021 AT 6:46 PM

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