TSB 22-2326 : "Moan Noise in the Rear Brakes When Driven in Reverse in Cold Weather or High Humidity"

[Ford Motor Company]

Can someone help me out and write up what do I have to tell the dealership to get it fixed!?
They say it's normal operation and won't do anything!

Hi there! I can look into your Bronco's noise concern on my end. To get started, could you please send a private message over with the name/location of your local Ford dealer and your Bronco's VIN?

 

[Andrezzi]

Did the TSB fix the issue?

Still hear it once in a while when its raining or damp. Not all the time though so its better but not gone completely.

 

[DirtyLuke]

Mine squeeked once just today for about half a second, after coming home from driving a very dusty road. First time in over a month (since the TSB). Before the TSB it foghorned every single time I put the car in reverse, no matter the environment, no matter the time of day.

 

[freqnc]

Print out this current TSB 23-2308 which is the current fix from Ford. Take to your dealership and have them perform the work per the TSB. There is no guarantee it will fix the sound your specific vehicle is making.

TSB 23-2308
Moan Noise In The Rear Brakes When Vehicle Is Driven In Reverse (R) In Cold Weather And/Or High Humidity, Supersedes 23-2041
https://static.nhtsa.gov/odi/tsbs/2023/MC-10244711-0001.pdf

Thanks for the clear info! This is however EXACTLY what I did, first they said that they have the parts but then said the parts were unavailable and backordered, this was some 3 months ago.
I just called another dealerhip and they seem helpful, appt is coming up soon and I'm excited to have this fixed!

 

[Dude]

Thanks for the clear info!
appt is coming up soon and I'm excited to have this fixed!

?

 

[Diegotom]

Hi all,

I had the repair done in Dec. '23. It was the latest version of the tsb, "23-2308 ".
The brakes were quite until a month ago. I live in south Florida so not cold here and not hot yet.
Wondering if anyone has gotten more than 2 months of quite brakes out of this repair?

Thanks

 

[Scapino]

I have a '21 BS Outer Banks. For the TSB, When I try to order the Caliper Mount Kit - Ford (DG9Z-2C150-B) the website says the part does not fit my vehicle and to order Caliper Retainer Kit - Ford (CV6Z-2C150-A).

Is there any reason why the TSB kit would not fit my '21 BS Outer Banks?

This thread has 12 pages, so not sure if this questions has been answered yet.

 

[Cursed Bronco]

I dropped my vehicle off for the recall today as I never got around to having the drain tube installed. I also hit them with the leaking water pump, leaking rear glass, and the brake moan. Dealer seemed pretty knowledgeable and all should be fixed tomorrow. I am getting the updated water pump + flush, new rear seal, and replacement caliper bolts as the tech mentioned. As other have mentioned, the brake sound seems to come back. I will keep it updated on if my sound returns as well.

 

[Mark S.]

Dealer seemed pretty knowledgeable and all should be fixed tomorrow.

Sounds like you've got a great dealership to work with.

 

[Cursed Bronco]

I dropped my vehicle off for the recall today as I never got around to having the drain tube installed. I also hit them with the leaking water pump, leaking rear glass, and the brake moan. Dealer seemed pretty knowledgeable and all should be fixed tomorrow. I am getting the updated water pump + flush, new rear seal, and replacement caliper bolts as the tech mentioned. As other have mentioned, the brake sound seems to come back. I will keep it updated on if my sound returns as well.

Update
It got chilly overnight so it was prime time to test the brake fix- Nope. Sounded exactly the same this morning. Probably not worth taking it back at this point until Ford figures out the issue more. Has anyone had success replacing the entire rear brake assembly with aftermarket? I would assume that would fix it, but it's a lot to shell out in lieu of a proper warranty fix.

 

[Mark S.]

Has anyone had success replacing the entire rear brake assembly with aftermarket? I would assume that would fix it, but it's a lot to shell out in lieu of a proper warranty fix.

There's no way to know if this will fix it or not, because no one seems to know specifically what's causing the resonance.

 

[Cursed Bronco]

There's no way to know if this will fix it or not, because no one seems to know specifically what's causing the resonance.

It is very peculiar indeed. Combined with the fact that it's a fleeting sound and doesn't repeat after the initial reversing, you would think it would be a bit easier to isolate the problem. Seems to be related to humidity and air temperature as it happens in cold dry air, but also if it's hot but has been raining. Ford has to employ way smarter engineers than me, so it's kind of silly to me it hasn't been properly identified.

 

[Mark S.]

It is very peculiar indeed. Combined with the fact that it's a fleeting sound and doesn't repeat after the initial reversing, you would think it would be a bit easier to isolate the problem. Seems to be related to humidity and air temperature as it happens in cold dry air, but also if it's hot but has been raining. Ford has to employ way smarter engineers than me, so it's kind of silly to me it hasn't been properly identified.

I believe it's almost certainly due to moisture on the brake rotor. Most report hearing the noise on the first brake application in cooler temperatures. As air cools it's able to hold less water vapor. The temperature at which air can hold no more water vapor is call the dew point. If air temperature and dew point are the same you generally get ground fog. If, however, the air temperature is within a few degrees of dew point then water vapor often will condense and collect on surfaces that are cooler, like grass, glass, or painted surfaces that have radiated away all their heat.

When you hear the brake noise it's almost certainly because moisture has collected on the rotor. You don't hear it on subsequent brake applications because the rotor has heated enough to evaporate the moisture and prevent further condensation.

If anyone plagued with this phenomenon is feeling particularly scientific they can test my theory. Pick a day when you have experienced the noise in the past--generally a cool, clear morning, or rainy morning. Go out early enough to apply enough heat to the rear rotor to evaporate any collected moisture. You could use a heat gun or even an ordinary blow dryer. You don't have to get it hot, just warmer than the dew point of the surrounding air. My bet is you won't hear the noise.

 

[Cursed Bronco]

I believe it's almost certainly due to moisture on the brake rotor. Most report hearing the noise on the first brake application in cooler temperatures. As air cools it's able to hold less water vapor. The temperature at which air can hold no more water vapor is call the dew point. If air temperature and dew point are the same you generally get ground fog. If, however, the air temperature is within a few degrees of dew point then water vapor often will condense and collect on surfaces that are cooler, like grass, glass, or painted surfaces that have radiated away all their heat.

When you hear the brake noise it's almost certainly because moisture has collected on the rotor. You don't hear it on subsequent brake applications because the rotor has heated enough to evaporate the moisture and prevent further condensation.

If anyone plagued with this phenomenon is feeling particularly scientific they can test my theory. Pick a day when you have experienced the noise in the past--generally a cool, clear morning, or rainy morning. Go out early enough to apply enough heat to the rear rotor to evaporate any collected moisture. You could use a heat gun or even an ordinary blow dryer. You don't have to get it hot, just warmer than the dew point of the surrounding air. My bet is you won't hear the noise.

That is what I am getting at. Rotors getting wet are a pretty common occurrence, so, to me, it looks it comes down to materials choice. Either for the rotors, or the friction material in the pads. That then brings me back to the original point of how is it not figured out yet? Barring some extremely odd interaction between the components, I would think it should be fairly easy to identify. I wonder if anyone has simply bought aftermarket rotors? If I am not mistake, I believe I have seen folks in this forum state that replacement pads may eliminate the problem

 

[Escape2Bronco]

I know I’m in the minority here but it normally only happens once when you first back up in the morning. I’ll deal with it when I change the rear pads in 10 years. I’m not saying this is what a 30-40k vehicle should sound like but in the overall scheme of things, it stops great and at the end of the day, that’s what is most important to me. YMMV

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