PLEASE help me diagnose this BRAKE issue! (rotational chirping/squealing)

[Thirty-Two]

Contamination would burn off with use of brakes. The tech seems to be scrambling to give an explanation where none is due. Video above is a perfect example of bearing failure. A "growl" would be expected further down the road, as it scores the interior of the hub.

Now this sound is clearly caused by friction, contact, rubbing, what have you. This all causes heat.
Have the car cooled down over night at the shop. In the morning have a tech take a short, normal drive. Very relaxed, very easy on the brakes, no more than 10 min. Just enough to get things warmed up and maybe get that noise. Have an infrared laser or a sensitive but cautious hand feel around the brakes, hubs, suspension. The brakes should be anywhere from warm to hot, while your suspension should be cool. Most importantly hub bearings that do their job do not induce friction, and therefore heat. The hub should be cool to very slightly warm. If the hub is hot, that is another sign that the hub components may be going bad. If there is any doubt drive another Fiesta ST on the lot or if you know somebody with a FiST with around the same mileage and driving condition that would be best. Compare them after a drive. Hopefully it'll at least help narrow down your options.

Any competent shop should have already done something like this.

But I would also stress in trying to drive the car as much as possible to get some wear in those brakes. Sometimes the solution is the simplest option.

Also relating to what the tech said, it's not always that bearings will cause a pull to either side. The only way you can really tell is to have everything properly aligned and with new tires, so it's the best way to rule out a possibility.

 

[Seijou]

Contamination would burn off with use of brakes.

That's what I thought too. But what confuses me is that the noise level did decrease about 60% by them cleaning off pads and rotors. Although, the main thing for me is that the noise is still present which means the underlying issue has still not been resolved.

Have the car cooled down over night at the shop. In the morning have a tech take a short, normal drive. Very relaxed, very easy on the brakes, no more than 10 min. Just enough to get things warmed up and maybe get that noise. Have an infrared laser or a sensitive but cautious hand feel around the brakes, hubs, suspension. The brakes should be anywhere from warm to hot, while your suspension should be cool. Most importantly hub bearings that do their job do not induce friction, and therefore heat. The hub should be cool to very slightly warm. If the hub is hot, that is another sign that the hub components may be going bad. If there is any doubt drive another Fiesta ST on the lot or if you know somebody with a FiST with around the same mileage and driving condition that would be best. Compare them after a drive. Hopefully it'll at least help narrow down your options.

Any competent shop should have already done something like this.

I have tried giving 'suggestions' many times, as it is obvious we don't know the root cause of the issue, but it seems to fall somewhat on deaf ears. I think part of it is because of the warranty process, i.e. how do they justify what work to do (what to inspect) if there is no obvious culprit? I think the other issue is that there is a bit of a disconnect between what I tell the service advisor, and what the tech actually does. The tech will do what he thinks is right based on his training and intuition, and sometimes it doesn't align with my feedback. In normal cases, I think this is somewhat acceptable, as he is the expert and I am not. But I'm just trying to help as we have no answers. I want the issue resolved just as much as they do. It's costing them time and money to continue working on the vehicle. It is also a burden on me to bring the vehicle back time and time again (not to mention the safety concerns I have in regards operation of the brakes in general).

I am thinking I should give them a bit of time, as they service advisor said they would slow down to try and figure out what's wrong. In a little while, if I don't hear back I will contact the service manager to touch base about a strategy for eliminating potential causes, narrowing the list of suspected problems, and honing in on the issue. Although I know that the problem is they don't have a list of suspected problems. I do keep encouraging them to troubleshoot other components. I'll emphasize this when I can contact the service manager.

 

[Superfly Snook]

Seijou I listened to your videos and the ones posted by wspec and there are similarities but it's always going to be hard to compare given different ambient conditions, recording devices, etc.

With regard to the dealer indicating a wheel bearing would sound deeper, maybe the Fiesta just sounds different than other cars? I am used to wheel bearings sounding more like a growl or grinding noise and not the squeaking noise in your video, but then again those were different cars and I wonder if our local Ford dealers have even had Fiesta's with bad bearings yet given how low mileage these cars are? I think it is a theory to keep on the list. Maybe it only presents when you brake and weight shifts to the front?

 

[Seijou]

I think it is a theory to keep on the list. Maybe it only presents when you brake and weight shifts to the front?

Absolutely agree. Whatever the problem is, it's definitely related to load being transferred to the front wheels during braking. As I mentioned, it is also more noticeable while braking downhill. I know one way to detect a bad bearing is to feel for movement in the wheel itself by shaking it while it's off the ground (with your hands in the 12 and 6 position, apply pressure to 12, then 6.. etc, and it should not wobble or make any noise). I'll keep pressing for more diagnostics.

 

[Seijou]

I spoke with the service manager this morning and they are still working on the vehicle. I think they are trying to diagnose the bearing. Unfortunately, no other information to report at this time.

 

[Superfly Snook]

Hope they get it sorted out and get you back out on the road soon!