Need help!!

[Anace0]

I did not try disableing the hill start. I used two different brake fluids. One came with the brake kit and the other from autozone.

 

[Anace0]

Does hill start hold all 4 wheels?

 

[wraith]

I recently had a similar brake adventure, rear passenger caliper wasn't letting go all the way. All other corners of the car seemed ok. It wasn't tight enough to lock up the wheel but enough that it would stop the car from coasting. First I heard it grabbing, then I smelled it, then got out to find the rotor glowing orange .

I took the caliper apart and couldn't really find anything wrong and put it back together. Now it seems to run ok but I'm terrified when this might randomly happen again.

I did upgrade to Mountune SS lines, Mountune track pads (description says ok for street too) and Castrol SRF fluid back in July/Aug but it's already been running fine for ~6 months until now.

I will most likely take it to a Ford dealership I just hope it's not a waste of time/money since it isn't currently happening.

 

[D1JL]

I had my car in for service at my dealer today.
While I was there I asked a close friend, the shop foreman if there was a TSB or if he had ever heard of anything like this.
It was also fortunate that there was a Ford Engineering Tech. Rep. in as well, both their answers were no.

I asked about the Hill Start Assist, and there answer was Highly Unlikely, as it would take 3 modules to fail at the same time.

They did say however that they have herd of aftermarket rotors and pads causing problems but again unlikely but possible.

Sorry, still no clues.

 

[Anace0]

I appreciate you guys trying to help me out. Car is still at the dealer with no clues what the issue is....

 

[Anace0]

Okay so i got a call from the dealer and they are saying that when they pull up on the pedal it releases the pressure. They are going to replace the booster and hope for the best!

 

[kivnul]

Glad to help.

 

[dsphil]

Did new booster fix the problem?

 

[Anace0]

Im not sure yet. Had a 5 day wait to get the part. I am expecting it to be done tomorrow. We will see. I will keep you guys posted on it.

 

[Anace0]

Dealer called today and said the booster fixed it. However they want to keep it an extra day to drive it again. Kinda makes me feel a littlw uneasy but I wouldnt be able to pick it up until Friday anyway. I will let you guys know if it is true fixed. Thanks again for all the help!

 

[Anace0]

I got my car back last night. Drives fine. Did notice a little heat from left rear wheel when i got home. Took it for a ride thus morning and seemed no different from the other wheels. Seems to be fixed.

 

[dsphil]

Most likely the rear vacuum chamber in the booster is not sealing causing the front chamber to press in the brake.

 

[Intuit]

.................. noticed the brake pressure wasnt releasing. Which causes all wheels to lock after a short period.

............... can reset the calipers and spin the wheels freely, however if you hit the brake pedal a few times with the car on or off it will lock the wheels. ...................

Only difference between having the car on or off is the engine pulling vacuum. By law the brake boosters are designed to retain enough vacuum for a few pedal presses, after the engine is cut off. Releasing vacuum and retesting would've confirmed this.

 

[tbST14]

I went through this same scenario of brake lockups for months. 2014 ST with only 16K miles, like new really. Dealer had it 4 times with the following attempted fixes: New rotors (small lip on edge), nope. Replace one caliper that appeared to be sticking, nope. Replace brake booster and various brake switches, nope. Replaced master cylinder, nope. Final part that fixed the issue was part number d2bz2c405e "ABS Control Unit".

This was worth 2.5 months cumulative time in the shop. I hope this shortcuts the diagnostic time for others in the same boat. Btw, it acted like hill assist, but I had that setting off.

 

[Intuit]

Did pulling the ABS fuse have any impact?

 

[tbST14]

Did pulling the ABS fuse have any impact?

I removed the fuse the first time and thought it went away. Then I did it again 2 weeks later (before the repair) and it still persisted, so removing the fuse in my case was not a conclusive indicator of a solution. I thought it was really strange the second time did not temporarily solve it like the first.

 

[Intuit]

Why the module would be intermittently interfering with braking when it's not even powered does sound really strange. After looking up more info on the internal construction of the ABS modulator, it becomes apparent that there was some physical problem with an internal valve.

https://www.repairsmith.com/blog/abs-module/

 

[tbST14]

Why the module would be intermittently interfering with braking when it's not even powered does sound really strange. After looking up more info on the internal construction of the ABS modulator, it becomes apparent that there was some physical problem with an internal valve.

https://www.repairsmith.com/blog/abs-module/

Yes, agreed on 'some physical problem with an internal valve', thanks for the diagram and the link. It's been fine for many months now.