2.3 vacuum brake boost failure

[Philly Big Bronco Boy]

UPDATE 8.30.22

Part was shipped and installed! I picked her back up this morning. I'm back in the game baby! Took a bit of time given supply chain issues, but Ford and my dealer made it right.

If you're running into the same issue at the time of this writing the part number needed changed to MB3Z-2420-F. User flip posted the service announcement. I shared this when I initially dropped off my vehicle and it helped my service department given it's such a new vehicle.

Hoping this thread helps others if experiencing these issues.

Thanks!

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Original post

2.3 base, 4 door bronco. Build date in November/December 2021. Delivery right before Christmas.

At around 7k miles I started having issues with the brakes. Brake light came on while driving. Every time I stopped & restarted the truck, the brake light turned off. Initially thought nothing of it. Brakes felt normal and was stopping without issue. Until one day while I was using regular cruise control on the highway. Went to brake and nothing but a rock solid pedal. Had to stomp on the pedal to push through the pressure before I was able to brake. After stopping and restarting vehicle light went off. I tried replicating the same situation and same thing happened except now with a loud crunching sound as I pressed through the hard pedal feel. I took it immediately to my dealer. After reading the forum it seems others have experienced similar issues. The dealer ordered a new vacuum line as it seems very likely it’s the vacuum assisted brake boost others have reported. After waiting for a month I started following up with both the dealer and ford directly. No one at ford has been able to give me a timeline yet on when the part(s) will be available. They gave me a loaner until my Bronco is ready, but they won’t let me drive it until the part comes in as it seems they’re concerned Brakes will fail altogether. I figured I’d just stop using cruise for awhile but no dice.

I love my Bronco, no regrets, just want the thing back as I already waited forever to get it to begin with. Stripped it down to base to get it during the initial release year, and I’ve already spent 1ks on aftermarket add one and was about to lift it and throw beefy tires/rims/ect.

Anyway, reason for the post. A couple questions.

- How long have others waited for vacuum parts? Vacuum line and vacuum sensor specifically
- Are there alternative manufacturer parts available that are more readily available? Aftermarket/3rd party
- Anyone know if this is just a part malfunction or if it’s engineering related? I really don’t want to have to work this every 7k miles. Hoping the former as I’m hearing it’s not an easy repair.

Just a last comment as I’ve been reading a lot about this over the last month and more in the last week. It seems Bronco is not alone in Fords line up with brake issues. The Baby Bronco has an open recall already with vacuum brake failure effecting some 100k vehicles… This is old tech so not sure how/why this is happening.

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[Deleted member 32220]

Well…let’s say turbo or supercharged engines, when doing what they do which is make boost in psi. That is the opposite of in. Hg Vacuum. There is no vacuum available in a high cruise control speed setting as the engine is seeing 1 to 2 psi. Steady state. That computer is more accurate than your foot. The vacuum bleeds down over time, they can check valve it all they want. Brake boosters are not designed to a high enough standard to be hermetically sealed. Neither are airplanes. What ford will do is implement software that opens the wastegate to get the engine back into a vacuum state. You will feel the loss of power this will happen as many times as they need it to keep the booster in some predetermined in hg. State via the vacuum sensor. Don’t worry the airplanes you fly in bleed psi. At a steady or controlled state as needed. more pressure, more bleed air, less pressure, open outflow valve.

 

[Philly Big Bronco Boy]

Well…let’s say turbo or supercharged engines, when doing what they do which is make boost in psi. That is the opposite of in. Hg Vacuum. There is no vacuum available in a high cruise control speed setting as the engine is seeing 1 to 2 psi. Steady state. That computer is more accurate than your foot. The vacuum bleeds down over time, they can check valve it all they want. Brake boosters are not designed to a high enough standard to be hermetically sealed. Neither are airplanes. What ford will do is implement software that opens the wastegate to get the engine back into a vacuum state. You will feel the loss of power this will happen as many times as they need it to keep the booster in some predetermined in hg. State via the vacuum sensor. Don’t worry the airplanes you fly in bleed psi. At a steady or controlled state as needed. more pressure, more bleed air, less pressure, open outflow valve.

This makes sense as the brake light was only coming on when the engine was under load, meaning highway speeds and/or hill climb if the hill was long. If it’s turbo that’s related to the issue could a secondary electronic vacuum be installed in parallel/tandem or as a replacement? Leed Brakes Electric Vacuum Pump Kit - Chrome Bandit Series (VP001C) https://a.co/d/cNduK1H
I know in some muscle cars these are added when the vacuum is lost due to engine tuning. It seems crazy to me that Ford would add vacuum assisted braking if the turbo was over riding the engines vacuum. I’d rather add a vacuum pump than feel loss of power when I likely need it during a lane merger.

 

[Deleted member 32220]

That would surely fix it.

 

[Philly Big Bronco Boy]

That would surely fix it.

Do you know if it could be run in tandem? Also, would a turbo blow off valve create more pressure, alleviate pressure, or make no difference other than sound cool? As an alternative to adding electronic vacuum.

https://www.cjponyparts.com/turbosm...port-2-3l-2-7l-bronco-2021-2022/p/TS02231082/

 

[Deleted member 32220]

Theoretically a blow off would get the motor back into a vacuum state sooner as it’s no longer recirculating the psi. I just don’t think it would be enough to make any meaningful difference. An electric vacuum pump surely would work and it would keep ford’s pesky computer from trying to get the motor back into a vacuum state.

 

[Philly Big Bronco Boy]

sorry for your trouble w this, and am not questioning the problem you've experienced

However at NHTSA site, I don't see a Bronco Sport recall w ' vacuum brake failure '

Bronco Sport has a recall for ' rear brake linings may have been manufactured incorrectly ' - ( below )
- affecting '21 & '22 Escape and Bronco Sport

in the Bronco 2.3L vacuum brake boost problems it does seem that cruise control is involved, usually

I found this thread on the Bronco Sport forum and there’s widespread discussion there on vacuum brake issues. Not sure if it’s the same parts that are failing but it seems like it’s definitely related to vacuum brake boost failure reading the letter Baby Bronco owners received directly.

I could be wrong, just browsing the internet for answers.

 

[Philly Big Bronco Boy]

I found this thread on the Bronco Sport forum and there’s widespread discussion there on vacuum brake issues. Not sure if it’s the same parts that are failing but it seems like it’s definitely related to vacuum brake boost failure reading the letter Baby Bronco owners received directly.

I could be wrong, just browsing the internet for answers.

Specifically the line referencing what is the issue and mention of vacuum failure

 

[Philly Big Bronco Boy]

it's interesting cause your printed page has the same NHTSA Campaign #, but the description at NHTSA website is very different

your printed page there definitely talks about vacuum brake booster failures in Bronco Sport

maybe the NHTSA website description is inaccurate ?
- they both have the same # 21V922

Yes, I saw that too. Agreed very strange. It seems what was sent to affected customers has more detail, and/or was slightly different? Not sure, but if you go on the sport forum very similar issue is being described.

 

[Philly Big Bronco Boy]

at NHTSA website here's latest update from July 14, '22

looks like they're having trouble finding root cause of long braking distances
- says July 14 Ford revised the owner notifications

looks sorta confused

Yes, a bit all over. It seems like it’s a failure in either the vacuum sensor, vacuum hose, or vacuum brake boost unit itself reading that. Which is about where I’m at with my full size Bronco. It could be either one of those three components from what I’m hearing from the dealers service department. Interesting that the notice mentions electronic brake boost vehicles aren’t effected.
I’m seriously considering just adding an aftermarket electronic vacuum booster. It would likely solve the issue and with Amazon I could resolve in two days rather than waiting on ford to manufacture more parts that may not even resolve the issue. I’m going to call my dealer and ford again tomorrow to see if doing so would void any engine warranty. I’m hoping not since it’s already broken… I just want my bronco back!

 

[Ford Motor Company]

2.3 base, 4 door bronco. Build date in November/December 2021. Delivery right before Christmas.

At around 7k miles I started having issues with the brakes. Brake light came on while driving. Every time I stopped & restarted the truck, the brake light turned off. Initially thought nothing of it. Brakes felt normal and was stopping without issue. Until one day while I was using regular cruise control on the highway. Went to brake and nothing but a rock solid pedal. Had to stomp on the pedal to push through the pressure before I was able to brake. After stopping and restarting vehicle light went off. I tried replicating the same situation and same thing happened except now with a loud crunching sound as I pressed through the hard pedal feel. I took it immediately to my dealer. After reading the forum it seems others have experienced similar issues. The dealer ordered a new vacuum line as it seems very likely it’s the vacuum assisted brake boost others have reported. After waiting for a month I started following up with both the dealer and ford directly. No one at ford has been able to give me a timeline yet on when the part(s) will be available. They gave me a loaner until my Bronco is ready, but they won’t let me drive it until the part comes in as it seems they’re concerned Brakes will fail altogether. I figured I’d just stop using cruise for awhile but no dice.

I love my Bronco, no regrets, just want the thing back as I already waited forever to get it to begin with. Stripped it down to base to get it during the initial release year, and I’ve already spent 1ks on aftermarket add one and was about to lift it and throw beefy tires/rims/ect.

Anyway, reason for the post. A couple questions.

- How long have others waited for vacuum parts? Vacuum line and vacuum sensor specifically
- Are there alternative manufacturer parts available that are more readily available? Aftermarket/3rd party
- Anyone know if this is just a part malfunction or if it’s engineering related? I really don’t want to have to work this every 7k miles. Hoping the former as I’m hearing it’s not an easy repair.

Just a last comment as I’ve been reading a lot about this over the last month and more in the last week. It seems Bronco is not alone in Fords line up with brake issues. The Baby Bronco has an open recall already with vacuum brake failure effecting some 100k vehicles… This is old tech so not sure how/why this is happening.

Hi! Will you send us a message with your VIN and dealership info? I would like to look into the part delay and see what I can do on my end.

 

[iamchewby]

If it's the same thing that happened to mine it's a known issue. Some of the 2.3's escaped the factory with "contamination" in the brake vacuum hoses. It's a quick fix, covered under warranty without question.

 

[Philly Big Bronco Boy]

Hi! Will you send us a message with your VIN and dealership info? I would like to look into the part delay and see what I can do on my end.

I’m in active dialogue with someone from ford directly. Both the dealer services dept and the support I’m receiving from a customer support perspective directly from ford has been great. I know it’s being looked into and ford is listening. It’s just part availability due to supply chain woes I’m sure. I’m anticipating a timeline from my customer rep at ford within the next 24 hours given my conversations. That said, if the timeline I receive is months out I’d like to explore either aftermarket or a ford electric vacuum pump. I’ll DM you around impact to warranty if I take this path.

 

[flip]

 

[Philly Big Bronco Boy]

Yes, I found this a month ago and shared with my ford Service Department when I dropped off the vehicle. That part number is what I've now been waiting over a month for unfortunately. Now I'm just trying to find out if they have it in stock and how long it'll take to be delivered.

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