Need help!!

[Anace0]

And i tried pulling the abs fuse which did nothing besides create lights. I forgot to mention that.

 

[dsphil]

Did you try to active the ABS by stopping the car hard before the car start to lock up?

 

[Anace0]

Yes i tried engaging the abs to see if it would fix and did not. The dealer its at now "said" they did an abs and manual bleed as well.

 

[dsphil]

Sorry to hear. Seems like have done everything in the book. Only master cylinder and abs module (maybe brake booster too) can do that to all 4 wheels. Oh, check the brake booster check valve?

 

[Anace0]

Im not sure what the brake booster check valve is? It creates the pressure without problem but will not release. Also pedal doesnt go to floor or anything

 

[Rocketst]

Check valves stop pressure or fluid from moving in the wrong direction. When they get blocked or clogged they can stay open and not allow a release of pressure.

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[Anace0]

Lol sorry i know what a check valve is. I was unaware the booster had one? Where is it located?

 

[kivnul]

I didnt try pulling up on the brake pedal? The boosted is non adjustable if thats what your getting at. And I didnt replace abs module or think its the issue because you can release the pressure all the way to the master. Crack line between master and abs and its fine until you touch the brakes.

When the brakes are locked/not releasing grab the break pedal and pull it towards you / upwards and see if it makes a change. I have heard of something like this before. If the pedal doesn't move then try something else I suppose.

 

[Anace0]

I would however the vehicle is at a ford dealership right now. Is ford on this forum? Would be a good time for corporate to get involved. Maybe send out a master tech?

 

[Rocketst]

Not sure where the check valve is exactly. I know its supposed to be right off the brake booster and master cylinder though. Check this link https://techtalk.mpbrakes.com/how-to-series/how-to-diagnosing-and-fixing-brake-drag and see if anything clicks. I will also second that about corporate. Corporate is very customer friendly. If they can do something to help their name they will. I had a problem with ordering black rims (6 month back order) dealership refused to give me money back. I called corporate and within 24 hrs dealership called me apologized and refunded my money

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[Rocketst]

Also, just be aware that the brakes for our car are actually an incredibly good system. They are one of the most expensive things to improve on because of their bite and performance they are really well made for the car. The only performance gainers in that area would either be brembos or willwoods. Dont get me wrong, I love stop tech stage 4s on my bmw 330i but thats because the 330i didn't have very good brakes to begin with. If the dealer recommends going back to stock pads it won't be a total loss. In this instance, stock could be better.

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[dsphil]

If you can release the pressure by disconnecting the lines at master cylinder, then the issue must be from the master cylinder to the brake pedals. If you replaced the master cylinder twice (what are the chances both are faulty), then it must be from the booster to the pedals. I can see that the spring in the booster may not return to it normal position after applying the brake causing the master cylinder shaft piston not returning to open the brake pressure. I would start investigate the booster and brake pedals. Maybe something went wrong during the bleed process got the mechanism in the booster or pedal assembly to become faulty. That's all I can think off if the ABS module has been ruled out. Follow the vacuum hose from the booster to locate the check valve, but I doubt it is the issue.

 

[Anace0]

I have never had a bad brake booster so correct me if im wrong but wouldn't that do the opposite and make it hard to engage the brakes or pedal just got to the floor? I dont think it can hold pressure? And wouldnt it stay locked when i crack a line?

 

[dsphil]

When you release the pressure from disconnecting the brake line from the master cylinder, did you check if the brake fluids will drain off it?

 

[Anace0]

Do you mean if it drips fluid out when i crack the line? Yes it does. Nothing crazy though

 

[Ford ST]

You're not the first person this has happened to but I don't remember if there was a fix. Something about these cars and the braking system. I have done a ton of brake jobs and I've never had any issues no matter what the process was. You're definitely not the first person to have this problem.

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[Anace0]

Ive done brake jobs quite a few times. I always work on my own cars whether its maintenance or mods. Ive never even heard of this before and ive yet to find someone that can figure it out.

If its happened to others, what was the resolution?

I called another ford dealer today. Im friends with the parts/service director.(I work for a different dealership btw) and was told they had a similar issue with a focus st and it was an issue with the bleeding.

Said they replaced 2600 bucks worth of parts and didnt fix it. Which is what the current ford dealer is trying to do. I have no problem paying for a fix, however i have a BIG problem with spending thousands for no reason

 

[dsphil]

Do you mean if it drips fluid out when i crack the line? Yes it does. Nothing crazy though

Not just crack the line, but completely remove the hard lines from the master cylinder. All the brake fluid should drain out. Try this, remove the brake reservoir cap, pump the brakes until the problem occurs. removed the hardline from the master cylinder. Wait to see if all the fluid will drain out or not. If it does, the master cylinder and from there up works properly. If it doesn't, then it is the master cylinder from there up has issues.

 

[dmb]

when the brakes lock up is the brake light on? I really don't know if the switch is hydro, but if the brake light is off maybe you should go in a different direction. just my 2 cents. also what brake fluid did you use?

 

[D1JL]

Did you try disabling the Hill start assist.
I am not sure if this is the cause but it is something I would try to be sure.