Brake pedal goes down to the floor?

Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
  • 1999 FORD F-150
  • 80,000 MILES
After putting on new brakes on the front of my truck I proceeded to bleed my brakes. All seems to go well until I start my truck and every time the brake pedal goes down to the floor. Why? Frustrated!
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Sunday, September 17th, 2017 AT 5:14 AM

40 Replies

Tiny
JIS001
  • EXPERT
When doing a brake pad change there should be no need to bleed the brakes. If you opened the bleeder screw to push the piston in then you may still have trapped air.

You will need to start with the right rear wheel, then left rear wheel, then right front, and left front wheels to bleed. If you have ABS and the pedal still feels a little soft, you will need a compatible scan tool to bleed the air out the ABS unit.
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Sunday, September 17th, 2017 AT 1:45 PM
Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
I will try this, although I did bleed all wheels this way already. I will let you know. Thank you!
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Sunday, September 17th, 2017 AT 1:49 PM
Tiny
CARADIODOC
  • EXPERT
Hi guys. Excuse me for butting in, but you are overlooking an important point. Besides no need to bleed the system, a lot of do-it-yourselfers AND inexperienced mechanics cause a problem by thinking it is necessary to pedal-bleed with a helper. The problem comes when they push the brake pedal all the way to the floor. That will often damage a master cylinder that is more than about a year old. Crud and corrosion build up in the bores where the pistons don't normally travel. Pushing the brake pedal to the floor, whether bleeding improperly, or when surprised by a sudden leak, runs the rubber lip seals over that crud and can rip them. That can result in a slowly-sinking pedal, and that often does not show up for a few days. It can also result in no brakes at all if both seals are torn.

If the truck has anti-lock brakes, it is correct that a scanner may be needed to command the computer to open two chambers so the air can be expelled, but only if you allowed the reservoir to run empty. That is another common mistake, but only when the hydraulic system is opened to replace a part. If you just slapped new pads on, which is just a fraction of a professional brake job, there is no need to bleed the system. It is recommended by every manufacturer to replace the brake fluid periodically, along with the moisture it absorbs, but few of us do that because the systems are so trouble-free. When you do that maintenance service, just let most of the old brake fluid run out, then fill the reservoir with clean, fresh fluid, and let that run through. As long as the reservoir never runs empty, no air can get in.

The only bleeding method I use is gravity-bleeding. No helper is required, but it does take a little longer. Loosen the cover on the reservoir to prevent vacuum from forming that would inhibit the free flow of the brake fluid. Open all the bleeder screws for just the wheels that need to be bled. If no fluid runs out after about five minutes, "irritate" the brake pedal a little, by hand, to get the flow started. When no more bubbles are coming out, close that bleeder screw, then wait for the next one to start flowing. When they are all closed, work the brake pedal a little by hand again to wash the few sticking bubbles into the calipers or wheel cylinders. Open each bleeder screw once more to let those few bubbles pop out, and you're done.

JIS001 mentioned pushing the pistons into the caliper housings. That is necessary to fit the new, thicker pads in place. Once everything is assembled, you have to manually run those pistons back out until the pads contact the rotors. If you reused the old rotors, they will be worn a little thinner than they were originally. The result is you may be able to push the brake pedal all the way to the floor before the pads make that initial contact and pedal pressure builds up. That can also damage the seals in the master cylinder. I tell my students to pretend there is a 4x4 block of wood under the pedal, and to never ever push the pedal past that block.

If it does appear you need to replace the master cylinder, I have a trick that eliminates the need to bleed at the wheels, but it works best when there are only two steel line connected to the master cylinder. Ford connects four lines, two on each side, to a lot of their vehicles. My trick still works on those, but it takes a little longer.
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Sunday, September 17th, 2017 AT 3:50 PM
Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
I replaced pad and rotors. Thank you. I am still having brake pedal issues! I appreciate all the information I can get!
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Monday, September 18th, 2017 AT 9:02 AM
Tiny
JIS001
  • EXPERT
Just like CARADIODOC suggested, if you bleed the system right and did a scanner bleed you will need to replace the master cylinder at this point.
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Monday, September 18th, 2017 AT 5:18 PM
Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
All is well finally! Thanks for all the help!
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Tuesday, September 19th, 2017 AT 3:04 AM
Tiny
CARADIODOC
  • EXPERT
Happy it's solved, but what was the solution?
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Wednesday, September 20th, 2017 AT 12:19 AM
Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
Bleeders in the wrong position. Totally my error. I knew better. I'm glad it was nothing more. Thanks again for all the help!
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Wednesday, September 20th, 2017 AT 12:32 AM
Tiny
CARADIODOC
  • EXPERT
I take it to mean the calipers were switched side-to-side. That seems to happen more than you would think.
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Wednesday, September 20th, 2017 AT 12:36 AM
Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
Exactly!
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Wednesday, September 20th, 2017 AT 6:12 AM
Tiny
KEN
  • ADMIN
Please use 2CarPros anytime, we are here to help. Please tell a friend.

Cheers, Ken
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Thursday, September 21st, 2017 AT 12:42 PM
Tiny
KITTYLEECO@YAHOO.COM
  • MEMBER
Thank you so much and I will surely pass this site to others!
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Thursday, September 21st, 2017 AT 12:46 PM
Tiny
SUNNYSUE48
  • MEMBER
  • 1999 FORD F-150
  • 5.4L
  • V8
  • 2WD
  • AUTOMATIC
  • 220,000 MILES
Have replaced front brakes, master cylinder, and have bleed brakes multiple times. Front passenger side wheel bearing was replaced before any other brake work was done. Have been told now to replace brake booster. Is this the next attempt to get brakes working again?
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Thursday, September 24th, 2020 AT 11:40 AM (Merged)
Tiny
SCGRANTURISMO
  • EXPERT
Hello,

It is if it is leaking or not helping to build pressure. Your vehicle's
brake system is just like a hydraulic system, and depends on brake fluid, under pressure to squeeze the calipers and apply pressure to the rotors, slowing your vehicle. The brake system must be intact with no leaks for this to happen or else the pressure in the system will bleed off. I have included a link for you to go to down below.

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

Please go through this guide and get back to us with what you find out.

Thanks,
Alex
2CarPros
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Thursday, September 24th, 2020 AT 11:40 AM (Merged)
Tiny
SUNNYSUE48
  • MEMBER
Thank you for your time and attention. I went through the guide you sent and can see no leaks anywhere. Going to have a friend look at the back brakes. So still stumped. But I will update when the back brakes are looked at. Any other suggestions are welcomed.
If after brakes are looked at and they appear fine, I suppose it will be trip to mechanic shop again.
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Thursday, September 24th, 2020 AT 11:40 AM (Merged)
Tiny
SUNNYSUE48
  • MEMBER
Also, brake fluid reservoir is full. The brake pedal is not being hard to push, it has no resistance at all.
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Thursday, September 24th, 2020 AT 11:40 AM (Merged)
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

Okay, you are sure you have bled the brakes completely? You had fluid coming out of the bleeder before you tightened it back up? I have included the Ford Factory Troubleshooting Guide for your vehicle's brake system in the diagrams below. Please go through the troubleshooting guide and please get back to us with what you find out, please.

Thanks,
Alex
2CarPros.
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Thursday, September 24th, 2020 AT 11:40 AM (Merged)
Tiny
POIPOIPOUNDER
  • MEMBER
  • 1999 FORD F-150
  • 2.0L
  • V8
  • 2WD
  • MANUAL
  • 100,000 MILES
Brake pedal goes to floor. Pumping doesn't work. Cylinder is full and not leaking. Brake Masters said brake pads good and no leaks.
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Thursday, September 24th, 2020 AT 11:41 AM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Good afternoon,

If the fluid is good and you have no pedal, most likely the master cylinder has failed.

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

If you open a bleeder, does fluid come out with the pedal depressed?

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

Roy
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Thursday, September 24th, 2020 AT 11:41 AM (Merged)
Tiny
POIPOIPOUNDER
  • MEMBER
I'm not able to do that. I'm not trusting Brake Masters answer because I can't afford to replace entire or rebuilt ABS as msgr is suggesting. Or he said bring title to him so he can dispose of truck.
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Thursday, September 24th, 2020 AT 11:41 AM (Merged)

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