After a complete brake job the front brakes will not release and the pedal goes to the floor

Tiny
CHAD READ
  • MEMBER
  • 1997 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 1,000 MILES
I replaced the master cylinder, replaced brake booster, new brake pads, turned rotors, replaced calipers. Tried bleeding brakes in sequence over and over, bench bled master cylinder. Front brakes squeeze together and won't let go. And pedal still sinks to the floor.
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Monday, January 21st, 2019 AT 10:26 AM

40 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
HI and thanks for using 2CarPros.

It sounds like an issue with one of the rubber brake hoses to the caliper. I need you to try this for me and let me know what happens.

First, safely lift the front wheels off the ground so you can turn them. Apply the brakes so the caliper locks. Open the bleeder on the brake caliper. Does the caliper release?

If so, do this. Apply the brakes to lock caliper. Release pressure at the master cylinder. If it doesn't release the caliper, replace the rubber brake hoses.

Here are the directions specific to your vehicle for brake hose replacement. The attached pictures correlate with these directions

Front brake hose
Removal:
Warning: brake fluid contains polyglycol ethers and polyglycols. Avoid contact with eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, flush eyes with running water for 15 minutes. Get medical attention if irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately.

- Raise and support the vehicle.

Warning: the electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle, this can be accomplished by turning off the air suspension switch located in the right hand kick panel area. Failure to do so may result in unexpected inflation ()r deflation of the air springs which may result in shifting of the vehicle during these operations.
Disconnect Front Brake Hose
see picture 1

- Disconnect the front brake hose.
1 Remove the front brake hose bolt.
2 Remove and discard the copper washers. Plug the front brake hose.
3 Disconnect the front brake hose.

Remove Front Brake Hose
see picture 2

- Remove the front brake hose.
1 Disconnect the front brake tube fitting and plug the tube.
2 Remove the plug;
3 Remove the two brake hose frame bolts.
4 Remove the front brake hose.

INSTALLATION:

Front Brake Hose Torque Specifications
see picture 3
Front Brake Hose Torque Specifications
see picture 4

- To install, reverse the removal procedure.
Bleed the front brakes; refer to procedure in this section section.
Let me know what you find.

________________________________________________

Also, since both the booster and master cylinder were replaced, you really should check the push rod adjustment between the two. Here are the directions for adjustment, Pic 5 correlates with this process.

Remove the brake master cylinder: refer to the Master Cylinder, Brakes.

Power Brake Booster To Master Cylinder Push Rod Torque Specification

see picture 5

-Adjust the power brake booster to brake master cylinder push rod.
1 Measure the power brake booster to brake master cylinder push rod.
2 If necessary, adjust the screw to the proper length.

Let me know what you find or if you have other questions.

Take care,
Joe
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Monday, January 21st, 2019 AT 5:43 PM
Tiny
CHAD READ
  • MEMBER
I forgot to mention I also replaced the brake hoses.
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Monday, January 21st, 2019 AT 6:16 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Okay. Did you adjust the push rod? It sounds like something isn't put together correctly there. If nothing leaks, everything is new, either the master cylinder is bad or the push-rod is not properly adjusted and getting stuck causing the pressure to remain on the calipers. Try the release procedure I suggested. At least that way we will know if the problem is at the master cylinder or after it.
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Monday, January 21st, 2019 AT 6:40 PM
Tiny
CHAD READ
  • MEMBER
I have not yet adjusted the push rod yet. Waiting for warmer weather I also already bench bled the master cylinder the best I could with the kit. So I will check the push rod first.
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Monday, January 21st, 2019 AT 6:48 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Let me know what you find. I hope that takes care of it.

Take care,
Joe
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Monday, January 21st, 2019 AT 6:50 PM
Tiny
CHAD READ
  • MEMBER
Thanks for the tips I will let you know as soon as I get to the source of the problem.
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Monday, January 21st, 2019 AT 6:55 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Sounds good, Chad. Take care and good luck. I will watch for your reply.

Joe
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Monday, January 21st, 2019 AT 7:01 PM
Tiny
CHAD READ
  • MEMBER
I adjusted the push rod the pedal hardend and remained hard even after it set. (No more sinking to the floor). The front brakes squeezed but they aren't letting go do you recommend bleeding all after?
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Tuesday, January 22nd, 2019 AT 10:33 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Okay, now that we have a good pedal, try to bleed the system. However, air in the system shouldn't cause the system to lock up. So, lets try to narrow it down. First, pump the brakes so the calipers lock. Once they do, open the bleeder on the caliper and see if the caliper releases. If it does, then we need to go further back. Close the bleeder at the caliper. Go the master cylinder, and apply brakes so they lock again and open the front steel line on the master cylinder and see if it releases. If it does, then something is bad in the master cylinder.

One other thought. There is a fluid control valve on the MC that's primary function is to control rear brake pressure. Did you reinstall it? I attached a picture of it.

Let me know.

Joe

PS: You did clean and lube the caliper slid pins, correct?
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Tuesday, January 22nd, 2019 AT 6:08 PM
Tiny
CHAD READ
  • MEMBER
I bought a new MC but it did not have the fluid control valve. So I put the old one on. And I cleaned and lubed the caliper pins and I did not tighten them too tight. I made sure I could move them back and forth easily.
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Tuesday, January 22nd, 2019 AT 8:01 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
Then pressure isn't able to return to the MC. Try the test I suggested and let me know the results. It's either fluid can't return or you got bad calipers and the pistons are sticking.

Take care,
Joe
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Tuesday, January 22nd, 2019 AT 9:01 PM
Tiny
CHAD READ
  • MEMBER
Ok Thanks
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Tuesday, January 22nd, 2019 AT 9:14 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
No problem. Let me know the results.

Joe
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Wednesday, January 23rd, 2019 AT 4:40 PM
Tiny
CHAD READ
  • MEMBER
Okay now fluid is coming out of all except the rear drivers side.
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Saturday, January 26th, 2019 AT 10:06 AM
Tiny
CHAD READ
  • MEMBER
Nevermind just had to prop the the pedal fluid shot out of the right front passenger side strongly. Fluid is coming out of all of them now pedal will sink to the floor after sitting a little bit.
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Saturday, January 26th, 2019 AT 10:23 AM
Tiny
CHAD READ
  • MEMBER
Pedal is hardening up front brakes arent letting go I did not completely bleed all of the brakes I just made sure fluid was coming out no air shot out I made sure fluid was coming out of the abs module no air came out of it. Is the an ABS valve somewhere on this truck? I dont know exactly where it is I can see anything.
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Saturday, January 26th, 2019 AT 10:41 AM
Tiny
CHAD READ
  • MEMBER
It seems like all the brake pressure is staying at the front alot more pressure on the passenger side than on the right and just a little fluid coming out of the back right and left and I noticed looks like there is a rubber brake hose tin the middle probably need to be replaced. What do you think.
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Saturday, January 26th, 2019 AT 11:38 AM
Tiny
CHAD READ
  • MEMBER
Should I try to get a new valve?
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Saturday, January 26th, 2019 AT 2:09 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
The valve may be the entire problem. It is what determines pressure to the rear. However, I have to be honest with you, I never saw one cause this. But, if the calipers release when you open the bleeder at the MC, that is my first suspect unless the new master cylinder is bad.

Was the vehicle doing the same thing prior to replacing the MC? If not, there may be an internal issue in the MC. There are two plungers. The one for the rear brakes may be bypassing fluid, causing the rear pressure to be low and causing some kind of build up of fluid which in turn doesn't allow the fronts to release.

Do the front brakes release when you open the bleeder?
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Saturday, January 26th, 2019 AT 5:49 PM
Tiny
CHAD READ
  • MEMBER
No they dont open. Yes if I remember correcly the same thing happened with the MC.
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Saturday, January 26th, 2019 AT 6:19 PM

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