Brake Help - Ford Can't Even Figure it Out

[Imoxfordwhite]

The problem me or Ford can't figure out:
When braking to a stop down a ~ 7% grade (or greater) the Bronco will stop, then start creeping forward for about a foot or so, then suddenly brake to a complete stop. My foot is pressed firmly against the brake pedal and there is no give when it starts creeping. When the truck starts creeping, I have no control of the vehicle and cannot press the pedal any harder to get it to stop.

My driveway is pretty steep and I can replicate this issue 100% in the morning when I head to work. However, after the truck is warm, I cannot replicate the issue.

I dropped the vehicle off at Ford and they cannot figure out the issue and gave the vehicle back to me with shrugged shoulders. I plan to take this truck to the backcountry soon but do not feel comfortable with how the brakes are acting.

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[Ducati1098]

You might want to add which engine as they have 2 different brake systems.
If it’s a 2.7, I’d guess an issue with the EBB.

 

[Imoxfordwhite]

You might want to add which engine as they have 2 different brake systems.
If it’s a 2.7, I’d guess an issue with the EBB.

I have the 2.7

 

[JohnnyBronco]

Have two people video you when this happens 1 on each side to determine if brakes are actually releasing or if 1 or more tires are losing traction for a moment. Hard to say if it is engine warm or tires warm when it does not occur.

 

[JohnnyBronco]

Also try using the e brake when it starts moving on its own.

 

[flip]

When it starts moving, does it feel like there's any brake holding, how much if so, or just a complete unrestrained roll?

Who did the lift? Were brake hoses clamped or removed when the lift was done? Any Forscan programming done to any modules? Has a ABS or traction light ever come on? Have you ever had to apply the brakes hard enough to cause ABS to engage (emergency stop)? Has your traction control system activated? I agree with @Ducati1098, likely something with the EBB or antilock system.

 

[Ford Motor Company]

The problem me or Ford can't figure out:
When braking to a stop down a ~ 7% grade (or greater) the Bronco will stop, then start creeping forward for about a foot or so, then suddenly brake to a complete stop. My foot is pressed firmly against the brake pedal and there is no give when it starts creeping. When the truck starts creeping, I have no control of the vehicle and cannot press the pedal any harder to get it to stop.

My driveway is pretty steep and I can replicate this issue 100% in the morning when I head to work. However, after the truck is warm, I cannot replicate the issue.

I dropped the vehicle off at Ford and they cannot figure out the issue and gave the vehicle back to me with shrugged shoulders. I plan to take this truck to the backcountry soon but do not feel comfortable with how the brakes are acting.

22' 4 Door Badlands w/ Sasquatch 2.7L - 4k miles (bought new)

Current Mods (Pic attached)
Full Icon Stage 8 Suspension
CBI Bumper
RCI Skids w/ Armor
Icon Tie Rods w/ Bushing
Warn Winch 12S w/ relocation kit
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Complete Sound System w/ JL TW12

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Hey there. I can look into your Bronco’s brake concerns on my end if you’d like. Will you send us a private message with your VIN and dealership info?

 

[Imoxfordwhite]

When it starts moving, does it feel like there's any brake holding, how much if so, or just a complete unrestrained roll?

Who did the lift? Were brake hoses clamped or removed when the lift was done? Any Forscan programming done to any modules? Has a ABS or traction light ever come on? Have you ever had to apply the brakes hard enough to cause ABS to engage (emergency stop)? Has your traction control system activated? I agree with @Ducati1098, likely something with the EBB or antilock system.

1. When the vehicle starts moving, the pedal is firm (I cannot press any further down, Ive tried) and it feels like the brakes are holding its slowly creeping forward. I have 0 control of when the brakes "catch" but it is always about a foot before jolting to a stop.

2. I installed the lift, and no brake work was touched. I was conscientious of the brake lines and abs sensors when installing.

3. ABS lights never come on. I have had 1 time where I hit the brakes hard enough where the ABS did engage.

4. Traction control system did engage 1 time in the snow.

I will get a video here soon to help better show the creeping forward.

 

[flip]

1. When the vehicle starts moving, the pedal is firm (I cannot press any further down, Ive tried) and it feels like the brakes are holding its slowly creeping forward. I have 0 control of when the brakes "catch" but it is always about a foot before jolting to a stop.

2. I installed the lift, and no brake work was touched. I was conscientious of the brake lines and abs sensors when installing.

3. ABS lights never come on. I have had 1 time where I hit the brakes hard enough where the ABS did engage.

4. Traction control system did engage 1 time in the snow.

I will get a video here soon to help better show the creeping forward.

Have to ask because of the frequency of it happening....are you 100% sure your foot/floormat isn't touching the accelerator when this occurs? Nothing touching the pedal or arm that would limit the travel?

Dealer is going to have to test a bunch of stuff and follow some pin point tests if there aren't any codes to work from but if you're rolling due to lack of pressure to the wheels, it's probably going to be in the hydraulic control unit. Internal linear actuator is what make the pressure but it also has internal valving that's used to regulate pressure to the individual wheels during ABS actuation, stability control and trac control. A valve or something sticking internally would make sense if this only happens when "cold". There may not be a specific test path that directly leads to the causal component so it may be one of those repairs that you try to eliminate everything else and try something. Not very scientific or logical but that's what happens with intermittent issues. Since this is a braking, aka safety system, I feel like it should get a little more attention than say a rattle someone hears once every two months. Ford says we need to duplicate a concern prior to performing/attempting a repair but there are cases like this that are in the grey area.

 

[Imoxfordwhite]

Have to ask because of the frequency of it happening....are you 100% sure your foot/floormat isn't touching the accelerator when this occurs? Nothing touching the pedal or arm that would limit the travel?

Dealer is going to have to test a bunch of stuff and follow some pin point tests if there aren't any codes to work from but if you're rolling due to lack of pressure to the wheels, it's probably going to be in the hydraulic control unit. Internal linear actuator is what make the pressure but it also has internal valving that's used to regulate pressure to the individual wheels during ABS actuation, stability control and trac control. A valve or something sticking internally would make sense if this only happens when "cold". There may not be a specific test path that directly leads to the causal component so it may be one of those repairs that you try to eliminate everything else and try something. Not very scientific or logical but that's what happens with intermittent issues. Since this is a braking, aka safety system, I feel like it should get a little more attention than say a rattle someone hears once every two months. Ford says we need to duplicate a concern prior to performing/attempting a repair but there are cases like this that are in the grey area.

100% sure there is nothing touching the gas pedal. The truck has no issue coming to a complete stop, but once settled, it starts creeping regardless of the braking pressure from my foot. Then will halt to a stop after about 1 foot of roll. Once it stops from that roll, the braking pressure still stays strong.

I have even had other people test this brake issue will the same results. The dealership had the truck for three days trying to replicate the issue with no success. It does appear the grade has a direct impact on this issue.

Note, I have four other vehicles that experience the same driveway with 0 issues.

 

[mj63]

Have to ask because of the frequency of it happening....are you 100% sure your foot/floormat isn't touching the accelerator when this occurs? Nothing touching the pedal or arm that would limit the travel?

Dealer is going to have to test a bunch of stuff and follow some pin point tests if there aren't any codes to work from but if you're rolling due to lack of pressure to the wheels, it's probably going to be in the hydraulic control unit. Internal linear actuator is what make the pressure but it also has internal valving that's used to regulate pressure to the individual wheels during ABS actuation, stability control and trac control. A valve or something sticking internally would make sense if this only happens when "cold". There may not be a specific test path that directly leads to the causal component so it may be one of those repairs that you try to eliminate everything else and try something. Not very scientific or logical but that's what happens with intermittent issues. Since this is a braking, aka safety system, I feel like it should get a little more attention than say a rattle someone hears once every two months. Ford says we need to duplicate a concern prior to performing/attempting a repair but there are cases like this that are in the grey area.

I would guess that you will end up having to demonstrate this to the service advisor and/or Ford field service engineer while they are recording CAN data in order to determine what is happening. It will likely be a long and frustrating path between now and then though. Keep telling them that given the your known circumstances/location you can repeat it reliably, and that they should record vehicle data while it happens in order to diagnose the root cause.

 

[HBTFD]

What happens if you shift into neutral during the “creep”?

 

[Imoxfordwhite]

What happens if you shift into neutral during the “creep”?

Ohhh this is a good idea. I'll try this tomorrow.

 

[BigMeatsBronco]

I would try turning off the traction control, then also the stability activtrac control ( hold the button down) and see if you can replicate it with one or both of these turned off....if you can't, then it's likely the ABS module or sensors.

 

[flip]

I can't remember if the HCU requires a RVC code (FDRS diag leads to failure and generates an approval code that's attached to the warranty claim to support payment), but if not there are alternate ways to get one.

If you have the VIN, send it to me in a DM. Curious to see if there's anything in your VHR that is related to your concern. The issue that's going on seems to be related to cold start/first drive and with some sort of grade. Some of the questions that need to be asked is if this is just the first drive cycle of the day or does it also happen after vehicle driven, parked in same place (driveway), few hours go by and it happens again? You ask me this question 15 years ago my initial response would be that the ABS system is going through a prove out. This usually happens within the first few seconds of the vehicle starting and customer putting in gear. They would feel the pedal pulse or have a brief pedal dip. If the vehicle was in park when it happened, they generally wouldn't notice it.

Another question. Have any of your tires been replaced? I'm talking about replacement of individual tires, not a full set, where you have a mix of new and worn. Are tire pressures in all tires the same? Again, going through the process of eliminating systems/components that are easy to see and measure.

Did this start after the bumper or any of the components were added? Was calibration for lane keeping and park aid checked after installation. Not sure either of these could cause your problem but since all this crap is networked, might be part of some sort of strategy that feeds into the problem. Since it happens on a grade, the sensors could be seeing an obstacle and some software coding is telling the brake system to do weird shit.

The dealer probably has a flight recorder as part of their VCMM kit they could hook up and let you drive for a few weeks. The older setup had a little trigger button you would hit when the problem happened and would capture the data a set number of seconds prior to, during and after the even. The kicker is you have to select the right PIDS to monitor so that the right system or sensor anomaly was registered. CAN systems are a royal biatch to diagnose to the point you need a waveform tool. You might suggest the flight recorder option from your dealer so you can continue using your vehicle since you have more insight to when this happens and will be able to anticipate the issue and get a better trigger to record the event.

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