brakes go to the floor
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Junior Member
Joined: Jan 2021
Posts: 1
brakes go to the floor
About 7 mouths ago my front wheel almost came off, it sat in a driveway for 6 mouths as i fixed it, When i drove it for the first time my brakes went to the floor and i felt like i had no pressure. i blead the brakes around 3 times on all sides filling the master cylinder each time so i dont have air in my brakes, i still had no pressure so i took it to a shop and they said that i blead the brakes well and that it was fine, im just wondering what could be causing this.
Senior Member
Joined: Apr 2020
Posts: 1,077
Are you losing brake fluid?
When you brake the pedal has no resistance and just keeps going till you hit the floor?
If you are loosing fluid but do not see any external leakage remove the booster vacuum hose and see if there is fluid in the booster.
Also if you don't agree with what one shop said then take it to another and don't tell them what you've done just that your brake pedal goes to the floor.
When you brake the pedal has no resistance and just keeps going till you hit the floor?
If you are loosing fluid but do not see any external leakage remove the booster vacuum hose and see if there is fluid in the booster.
Also if you don't agree with what one shop said then take it to another and don't tell them what you've done just that your brake pedal goes to the floor.
Senior Member
Joined: Apr 2019
Posts: 1,236
We have no idea what year your truck is. If fluid leaked out(emptied) where you had to fill it up, you will need a scan tool to properly bleed because of the ABS.If that wasn't the case, you have a full M/C with fluid, you bled properly, I would say your master cylinder is bypassing fluid and needs replacement.
Senior Member
Joined: Jun 2010
Posts: 16,567
There is some missing info here, but we can be sure of one thing,
If,,,,,,,,,,,,,,the master cyl has been on there for a few years, it has accumulated abrasive particles in the bottom of the master cyl bore. When the pedal went to the floor it ran the rubber cups on the master cyl parts over this abrasive "stuff" and scored them to the point they will not hold pressure, leak internally , and no amount of bleeding will correct that. The master cyl now needs to be replaced and of course , bench bled before installation, During normal braking the pedal only went down so far and this wall of grit was always ahead of the cups. Once the cups are dragged over that "stuff" , it's game over.
Once the master cyl is replaced, you can remove the retaining ring that prevents the pieces from coming out, they will come out and you will be able to observe the score marks on the cups.
If,,,,,,,,,,,,,,the master cyl has been on there for a few years, it has accumulated abrasive particles in the bottom of the master cyl bore. When the pedal went to the floor it ran the rubber cups on the master cyl parts over this abrasive "stuff" and scored them to the point they will not hold pressure, leak internally , and no amount of bleeding will correct that. The master cyl now needs to be replaced and of course , bench bled before installation, During normal braking the pedal only went down so far and this wall of grit was always ahead of the cups. Once the cups are dragged over that "stuff" , it's game over.
Once the master cyl is replaced, you can remove the retaining ring that prevents the pieces from coming out, they will come out and you will be able to observe the score marks on the cups.
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