Front disc brake noise when braking hard?

[Sloth]

Well the LBS has a look at the brake on Saturday and reported that so far as they could tell it was all fine.
Went for a ride on Sunday and again the high pitched ‘ticking’ from the front brake was still there when braking very hard down a hill to a junction.
It’s weird though as it doesn’t do it when braking reasonably hard in other situations???
I guess I’ll just have to live with it 😞

 

[8mph]

It's normal for disks to flex a little when the brakes are applied, this can sometimes bring the disk edge into contact with the caliper. It might help to recenter the brakes, or perhaps you need thicker washers to raise the calipers away from the disk.

 

[Sloth]

Thanks, I will check the alignment but it doesn't seem to be catching when I spin the wheel around.
I will also check the disc is not warped or out of true, but again it isn't catching on the pads at all.
I'm wondering if the calliper spring is somehow not located correctly or been bent somehow?
The rapid, high pitched 'ticking' (almost like a watch or small clock) when braking hard, does sound like it could be caused by thin flimsy metal, like the spring.
Worth a check, although I'm not sure how obvious it would be (and it would have to be obvious for me!)

 

[8mph]

Thanks, I will check the alignment but it doesn't seem to be catching when I spin the wheel around.
I will also check the disc is not warped or out of true, but again it isn't catching on the pads at all.
I'm wondering if the calliper spring is somehow not located correctly or been bent somehow?
The rapid, high pitched 'ticking' (almost like a watch or small clock) when braking hard, does sound like it could be caused by thin flimsy metal, like the spring.
Worth a check, although I'm not sure how obvious it would be (and it would have to be obvious for me!)

When I read your post I had a vague recollection of something similar going on with my brakes but as long as there's sufficient space between the top of the disk and the caliper body it must be something else

 

[Ming the Merciless]

Are the metal spring arms between the pads contacting the rotor arms on hard braking? Are the arms slightly bent?

 

[Sloth]

I’m going to have a more in depth look at the weekend.
I’ll check my pads as well whilst I’m checking the spring and perhaps clean them up if they look mucky.
Also clean up my disc just to be sure.
Keeps me out of trouble I suppose 😉

 

[Sloth]

OK, I stripped the front brakes down yesterday. I immediately saw what could be the issue. Deep gouges in the one of the pads.





Upon removing and inspecting the disc rotor, I could see no obvious edges or burrs that would explain such a deep gouge in the pad. Perhaps a stone or something got stuck, caused the damage and then worked loose and fell out? I don't know. I did clean up the rotor and re-fit it.

The pad spring seems fine, no damage or obvious mis-shape. I cleaned it anyway, as well as inside the brake piston housing to ensure (as best as I can see) no foreign bodies were stuck in there.

I then used meths to clean up the pads (they were filthy) and then some fine emery paper to resurface them, and to try and remove the gouge in one of them as best as I could.
I then cleaned them again with meths and left indoors to dry fully.
Here's them after cleaning, the one on it's own is the one that had the gouge in it...

 

[Alex321]

OK, I stripped the front brakes down yesterday. I immediately saw what could be the issue. Deep gouges in the one of the pads.


View attachment 711833
View attachment 711834

Upon removing and inspecting the disc rotor, I could see no obvious edges or burrs that would explain such a deep gouge in the pad. Perhaps a stone or something got stuck, caused the damage and then worked loose and fell out? I don't know. I did clean up the rotor and re-fit it.

The pad spring seems fine, no damage or obvious mis-shape. I cleaned it anyway, as well as inside the brake piston housing to ensure (as best as I can see) no foreign bodies were stuck in there.

I then used meths to clean up the pads (they were filthy) and then some fine emery paper to resurface them, and to try and remove the gouge in one of them as best as I could.
I then cleaned them again with meths and left indoors to dry fully.
Here's them after cleaning, the one on it's own is the one that had the gouge in it...
View attachment 711835
View attachment 711836

And has the noise gone?

 

[Sloth]

Don't know yet, I've not had chance to ride since I did it yesterday afternoon.
I hope to try tomorrow so will update then.
I was wondering in the meantime, if anyone had seen similar pad damage and if it could be the cause?

 

[Alex321]

Don't know yet, I've not had chance to ride since I did it yesterday afternoon.
I hope to try tomorrow so will update then.
I was wondering in the meantime, if anyone had seen similar pad damage and if it could be the cause?

I can't say I've seen anything similar, but it certainly could be the cause.A small projection on the rotor, whether a nick in the metal or a piece of stuck grit, would come round once per revolution of the wheel, and might only be noticeable under hard braking, but would leave that sort of damage.

 

[Sloth]

Yes, I suspect a transient piece of crap got stuck between the disc and pad, damaging the pad before then falling out again.
No sign of scouring on the disc though.