Another 2.3 brakes issue thread: it's a real problem this time

[JohnHunter]

TLDR: Vehicle is losing brake pressure when steering wheel is turned to the extreme and coming to a stop.

2.3 Badlands SAS. A few weeks back I began noticing occasional loss of brake pressure when moving at slow speeds, and particularly when parallel parking. The brake pedal loses most of its pressure and reaches all the way to the floor. aka spongy brakes.

I brought the Bronco to the dealership service to have a look at the brake system. They could not reproduce the problem, but bled the brake lines anyway for good measure. Unfortunately bleeding the brakes didn't help and the problem persists.

It took me a few days of trial and error, but I can now reliably reproduce the problem. I've narrowed it down to the brakes losing pressure when the steering wheel is turned to it's extreme (e.g. when parallel parking.)

Steps to reproduce:
1. Pull up next to the car in front of the spot I intend to pull into.
2. Put the car in reverse and cut the wheel all the way.
3. Begin pulling into the spot.
4. Get the ass end into the spot and cut the wheel all the way in the opposite direction.
5. Apply brake. Brakes lose pressure and I need to sink the brake pedal all the way to the floor to bring the car to a complete stop.

Has anyone experienced this problem before? Is there anyone mechanically inclined who can weigh in on the problem? Ideally it would be great if there is a Ford engineer on the board who can provide some insight.

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[mj63]

Just out of curiosity, do you have different diameter tires on the vehicle than what it was built with/configured for? If so, it might be some sort of corruption of the ABS reference speed and ABS thinking that the tires are slipping/skidding.

 

[Solfive]

Are you lifted? If so, how high?

 

[BAronco]

TLDR: Vehicle is losing brake pressure when steering wheel is turned to the extreme and coming to a stop.

2.3 Badlands. A few weeks back I began noticing occasional loss of brake pressure when moving at slow speeds, and particularly when parallel parking. The brake pedal loses most of its pressure and reaches all the way to the floor. aka spongy brakes.

I brought the Bronco to the dealership service to have a look at the brake system. They could not reproduce the problem, but bled the brake lines anyway for good measure. Unfortunately bleeding the brakes didn't help and the problem persists.

It took me a few days of trial and error, but I can now reliably reproduce the problem. I've narrowed it down to the brakes losing pressure when the steering wheel is turned to it's extreme (e.g. when parallel parking.)

Steps to reproduce:
1. Pull up next to the car in front of the spot I intend to pull into.
2. Put the car in reverse and cut the wheel all the way.
3. Begin pulling into the spot.
4. Get the ass end into the spot and cut the wheel all the way in the opposite direction.
5. Apply brake. Brakes lose pressure and I need to sink the brake pedal all the way to the floor to bring the car to a complete stop.

Has anyone experienced this problem before? Is there anyone mechanically inclined who can weigh in on the problem? Ideally it would be great if there is a Ford engineer on the board who can provide some insight.

My brakes are always really spongy with a 2.3 non SAS. It just feels wrong. Anyone else have that problem?

 

[Lifeliberty]

My brakes are great.
2.3 all stock sas

 

[JohnHunter]

Just out of curiosity, do you have different diameter tires on the vehicle than what it was built with/configured for? If so, it might be some sort of corruption of the ABS reference speed and ABS thinking that the tires are slipping/skidding.

All stock everything. Tires, wheels, suspension, brakes.

 

[JohnHunter]

Are you lifted? If so, how high?

No lift other than what SAS provides!

 

[JohnHunter]

My brakes are always really spongy with a 2.3 non SAS. It just feels wrong. Anyone else have that problem?

My brakes felt fine until I started experiencing this problem.

 

[Solfive]

Scary man! Glad it hasn’t resulted in an accident, even at low speeds. Hopefully someone here will have experience or good advice for you.

 

[Lcubed]

TLDR: Vehicle is losing brake pressure when steering wheel is turned to the extreme and coming to a stop.

2.3 Badlands SAS. A few weeks back I began noticing occasional loss of brake pressure when moving at slow speeds, and particularly when parallel parking. The brake pedal loses most of its pressure and reaches all the way to the floor. aka spongy brakes.

I brought the Bronco to the dealership service to have a look at the brake system. They could not reproduce the problem, but bled the brake lines anyway for good measure. Unfortunately bleeding the brakes didn't help and the problem persists.

It took me a few days of trial and error, but I can now reliably reproduce the problem. I've narrowed it down to the brakes losing pressure when the steering wheel is turned to it's extreme (e.g. when parallel parking.)

Steps to reproduce:
1. Pull up next to the car in front of the spot I intend to pull into.
2. Put the car in reverse and cut the wheel all the way.
3. Begin pulling into the spot.
4. Get the ass end into the spot and cut the wheel all the way in the opposite direction.
5. Apply brake. Brakes lose pressure and I need to sink the brake pedal all the way to the floor to bring the car to a complete stop.

Has anyone experienced this problem before? Is there anyone mechanically inclined who can weigh in on the problem? Ideally it would be great if there is a Ford engineer on the board who can provide some insight.

does the brakes come back to pressure afterwards?
or after restarting the engine?
or turning the steering wheel away from the extreme position?

it almost sounds like you're crimping the vacuum line at extreme steering position

of course, it could be this:

https://www.bronco6g.com/forum/threads/2-3-vacuum-brake-boost-failure.51629/

 

[goatman2]

If it only happens when the wheel is turned to lock, like when parking, I would check to see if the brake caliper is pushed against the control arm for some reason. I have experienced this with Jeeps. If the caliper is pushed against the control arm then the pedal can go to the floor with no resistance since the caliper has been artificially pushed so isn't completely sitting against the brake pads. Would be strange for this to happen on a totally stock Bronco, but it would explain what you are experiencing. If you can reproduce it any time, then I would make it happen and see if one push of the brake pedal corrected the problem. If so I would strongly suspect the caliper is hitting something.

 

[JohnHunter]

does the brakes come back to pressure afterwards?
or after restarting the engine?
or turning the steering wheel away from the extreme position?

it almost sounds like you're crimping the vacuum line at extreme steering position

of course, it could be this:

https://www.bronco6g.com/forum/threads/2-3-vacuum-brake-boost-failure.51629/

The brakes do come back to pressure after turning the wheel back to a less extreme angle. Pumping the brakes seems to help too. Agreed that it seems like either the vacuum line or maybe somehow the brake line getting choked. It also happens in both directions, extreme left and right.

 

[JohnHunter]

If it only happens when the wheel is turned to lock, like when parking, I would check to see if the brake caliper is pushed against the control arm for some reason. I have experienced this with Jeeps. If the caliper is pushed against the control arm then the pedal can go to the floor with no resistance since the caliper has been artificially pushed so isn't completely sitting against the brake pads. Would be strange for this to happen on a totally stock Bronco, but it would explain what you are experiencing. If you can reproduce it any time, then I would make it happen and see if one push of the brake pedal corrected the problem. If so I would strongly suspect the caliper is hitting something.

Thanks! I'll give this information to the mechanic.

 

[JohnHunter]

Last spring/summer wasn't there a known problem with some factory debris in the vacuum lines causing brake problems ? Have this vague memory that Ford was replacing lots of the vacuum lines/fittings around that time

Tomorrow you could ask @flip
He would know

Thanks. Will add to the list of things for dealer mechanic to check. I know little about these things, so I bet the mechanic would absolutely love for me to give him advice.

 

[Area51BS]

The brakes do come back to pressure after turning the wheel back to a less extreme angle. Pumping the brakes seems to help too. Agreed that it seems like either the vacuum line or maybe somehow the brake line getting choked. It also happens in both directions, extreme left and right.

Not sure how a choked or pinched brake line would cause pedal to become spongy or bottom out. No different than folding over a garden hose to remove nozzle while water is on. Pressure stays same between faucet and pinch.

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