Help me FINALLY fix my brake issues please.

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Help me FINALLY fix my brake issues please.
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flag tpiini
Posted: Oct 8, 2021 at 13:19 Quote
Hey Folks,

I've got a 2012 Ibis 26" with all XTR components that I put together new. I'm not really an aggressive rider, but was just in a position many years ago to spend money on good components. Not too terribly long after putting it together my brakes became very noisy and didn't grip very well. Over the years I've replaced pads and rotors, even changing sizes of rotors, only to never solve this problem. I've also replaced both calipers and one lever with newer XTR pieces.

I've currently got a set of metallic Shimano-branded pads that I put in it about a year ago. I even replaced both rotors at the time. It seemed at that time to finally be braking well and quietly. Sadly, some injuries and a few orthopedic surgeries have taken me out of the game for about a year ofter only riding it a few times with the new pads and rotors.

Today I finally got back on the bike and immediately had horrible brake squealing and very poor braking force from both ends. Great. After the very short ride I took everything apart for the umpteenth time and again found the pads and rotors were nasty and black. Brake Clean, 220-grit sanding, and they squeal less.

In contrast, my wife has been through four different bikes since I put this Ibis together. All of her bikes have had bargain basement Shimano or SRAM components and her brakes have NEVER squealed or faded. She had a knee injury about a year ago and has also been off of her bike for about 8 months. She had no brake issues on today's short ride

I've been meticulous about cleanliness and bedding the new pads in. Everything is aligned and torqued properly. New pads haven't helped. New rotors haven't helped. New calipers haven't helped. I'm ready to throw these "nice" XTR brakes in the trash and pop for a $100.00 set of hydraulic junkers for this bike.

Anyone care to sell me some clues? I'm seriously out of ideas.
flag TimMog
Posted: Oct 8, 2021 at 13:42 Quote
The fact you've replaced everything, and it still happens, suggests that initial setup may be the problem. Take some photos of your calipers straight on, that might help us see what the issue is
flag TimMog
Posted: Oct 8, 2021 at 13:43 Quote
And a video of the squealing
flag tpiini
Posted: Oct 8, 2021 at 18:02 Quote
TimMog wrote:
The fact you've replaced everything, and it still happens, suggests that initial setup may be the problem. Take some photos of your calipers straight on, that might help us see what the issue is

Well… not only do I work on this bike, but I’ve set up all of my wife’s bikes. And a lot of my friends bikes. Everything is aligned properly. I’ve even changed rotor diameters, and thus, caliper mounts to accommodate the different diameters. Both wheels spin freely and the calipers are spaced properly so that both pads contact the rotors evenly when pressure is applied. I’ve been so frustrated by this bike that I’ve gone as far as to purposely misalign the calipers in several ways in hopes of finding a solution. But to no avail.

In the years that I’ve had this bike I’ve been working on probably ten other bikes and none of them have any brake squeal or poor braking performance. The only thing different here is that I’m using XTR brakes on a carbon fiber bike. I set up another Ibis for a friend and he used cheaper SRAM brakes. No issues. I’m honestly hoping that someone else with XTR stuff can chime in and say they’ve had the same problem.

If it was just one end I feel I could chalk it up to a defect in either the forks or the rear frame. But it’s both front and back equally.

As for recording the squeal, well… let me just say that it can be heard from several hundred feet away. I’m not sure I’ve EVER heard brakes moan/squeal like this. It will do it at a slow walking pace or at 25 MPH. But next time I take it out I’ll shoot a video.
flag TimMog
Posted: Oct 9, 2021 at 8:52 Quote
You've noted that the pads and rotors are going black, very soon after thoroughly cleaning. That contamination is coming from somewhere - checked to see if the banjo is leaking?
flag tpiini
Posted: Oct 9, 2021 at 9:22 Quote
TimMog wrote:
You've noted that the pads and rotors are going black, very soon after thoroughly cleaning. That contamination is coming from somewhere - checked to see if the banjo is leaking?

My first thought was just that: leaking fluid. Definitely not from the banjos. But I wonder if some fluid doesn’t somehow seep past the piston o-rings. But the backs of the pads always seem to be clean.

I snapped a couple of pix then realized that I don’t even have to go for a ride to video the noise. Just a slow walk with light brake pressure will do just fine. Now to figure out how to load the pictures and videos here.
flag tpiini
Posted: Oct 9, 2021 at 9:29 Quote
Still trying to figure out pix and video…

Couldn’t figure out how to upload here, so a quick minute on YouTube will do:

https://youtu.be/tpApM7AfCbc

Well Shoot; apparently I can’t get it to “link” here. But I guess we can all copy & paste. Sorry for my internet ignorance. I guess at 61 years old I’m happy to just be able to turn on the computer.
flag tpiini
Posted: Oct 9, 2021 at 9:49 Quote
BTW: yesterday I disassembled and cleaned all of the rotors and pads after my ride then went for a quick heat-up-bed session. This is actually better than it was previous to that.
flag Davec85
FL
Posted: Oct 9, 2021 at 15:40 Quote
tpiini wrote:
Still trying to figure out pix and video…

Couldn’t figure out how to upload here, so a quick minute on YouTube will do:

https://youtu.be/tpApM7AfCbc

Well Shoot; apparently I can’t get it to “link” here. But I guess we can all copy & paste. Sorry for my internet ignorance. I guess at 61 years old I’m happy to just be able to turn on the computer.

Any time I have had that issue I have removed the pads, sprayed them with disc brake cleaner and sanded them when still wet. I then spray and repeat about 3-4 times until the top surface of the pad is removed. You can tell when you achieve this as the pad surface looks like a new pad. I then clean the discs with brake cleaner, 2 or 3 applications. Put it all back together, re-bed the brakes and they are sorted.

I've just done this today as my hard tail has not seen action in a while and the front brake was squealing exactly how yours is in the video. After doing the above, no more sqeal. Not really sure why it happens, but the bike sitting around for 6 months without being ridden seemed to cause it.

What products do you use to clean the bike? Do you use GT85 at all? Or any of those frame protect sprays etc? All culprits for causing this problem, and it only takes a very small amount (for example, using gt85 to displace water on the chain after washing and a light breeze carries it to the rotor).
flag iffy
Posted: Oct 9, 2021 at 15:56 Quote

sounds like contaminated pads.

aerosols can travel a long way, its possible that using one in the vicinity of the bike may cause this.

I have no idea why it would not affect the other bikes you have though..
flag tpiini
Posted: Oct 11, 2021 at 6:24 Quote
Davec85 wrote:
tpiini wrote:
Still trying to figure out pix and video…

Couldn’t figure out how to upload here, so a quick minute on YouTube will do:

https://youtu.be/tpApM7AfCbc

Well Shoot; apparently I can’t get it to “link” here. But I guess we can all copy & paste. Sorry for my internet ignorance. I guess at 61 years old I’m happy to just be able to turn on the computer.

Any time I have had that issue I have removed the pads, sprayed them with disc brake cleaner and sanded them when still wet. I then spray and repeat about 3-4 times until the top surface of the pad is removed. You can tell when you achieve this as the pad surface looks like a new pad. I then clean the discs with brake cleaner, 2 or 3 applications. Put it all back together, re-bed the brakes and they are sorted.

I've just done this today as my hard tail has not seen action in a while and the front brake was squealing exactly how yours is in the video. After doing the above, no more sqeal. Not really sure why it happens, but the bike sitting around for 6 months without being ridden seemed to cause it.

What products do you use to clean the bike? Do you use GT85 at all? Or any of those frame protect sprays etc? All culprits for causing this problem, and it only takes a very small amount (for example, using gt85 to displace water on the chain after washing and a light breeze carries it to the rotor).

I’ve gone through so much brake cleaner and have sanded so many sets of pads and rotors over the years that I can’t even begin to guess how much or how often. I’m so over this bike. I do nothing different with this bike than I do with any other bike, yet this one is a constant problem child. I’ve ordered the cheapest set of organic pads I could find and I’ll be throwing them in soon. If that doesn’t fix it my only other choice is to replace these XTR brakes with something else. It makes no sense to me. I’ve had four mountain bikes and my wife has gone through five. I’ve maintained them all and stored them all in the same way. But for some reason this one just won’t work properly.

As far as cleaning products, just water with some Dawn dish soap. I use chain wax, but am careful with the application. But again, I’ve done the same with every other bike and this one has been the only one that’s ever given me fits like this.

I wonder if the minimal weight of the XTR calipers allows for more vibration and thus sets up a harmonic. I’m really thinking a cheaper clunkier set of brakes is in my future.
flag Davec85
FL
Posted: Oct 11, 2021 at 7:20 Quote
tpiini wrote:
Davec85 wrote:
tpiini wrote:
Still trying to figure out pix and video…

Couldn’t figure out how to upload here, so a quick minute on YouTube will do:

https://youtu.be/tpApM7AfCbc

Well Shoot; apparently I can’t get it to “link” here. But I guess we can all copy & paste. Sorry for my internet ignorance. I guess at 61 years old I’m happy to just be able to turn on the computer.

Any time I have had that issue I have removed the pads, sprayed them with disc brake cleaner and sanded them when still wet. I then spray and repeat about 3-4 times until the top surface of the pad is removed. You can tell when you achieve this as the pad surface looks like a new pad. I then clean the discs with brake cleaner, 2 or 3 applications. Put it all back together, re-bed the brakes and they are sorted.

I've just done this today as my hard tail has not seen action in a while and the front brake was squealing exactly how yours is in the video. After doing the above, no more sqeal. Not really sure why it happens, but the bike sitting around for 6 months without being ridden seemed to cause it.

What products do you use to clean the bike? Do you use GT85 at all? Or any of those frame protect sprays etc? All culprits for causing this problem, and it only takes a very small amount (for example, using gt85 to displace water on the chain after washing and a light breeze carries it to the rotor).

I’ve gone through so much brake cleaner and have sanded so many sets of pads and rotors over the years that I can’t even begin to guess how much or how often. I’m so over this bike. I do nothing different with this bike than I do with any other bike, yet this one is a constant problem child. I’ve ordered the cheapest set of organic pads I could find and I’ll be throwing them in soon. If that doesn’t fix it my only other choice is to replace these XTR brakes with something else. It makes no sense to me. I’ve had four mountain bikes and my wife has gone through five. I’ve maintained them all and stored them all in the same way. But for some reason this one just won’t work properly.

As far as cleaning products, just water with some Dawn dish soap. I use chain wax, but am careful with the application. But again, I’ve done the same with every other bike and this one has been the only one that’s ever given me fits like this.

I wonder if the minimal weight of the XTR calipers allows for more vibration and thus sets up a harmonic. I’m really thinking a cheaper clunkier set of brakes is in my future.

So weird. If it's not contamination then it has to be some sort of harmonic Are the bolts holding the disc to the hub torqued correctly?
flag iffy
Posted: Oct 11, 2021 at 13:06 Quote
you could do a caliper swap with one of your other bikes

if the problem persists then its time for voodoo shit lol
flag eshew
Posted: Oct 11, 2021 at 13:39 Quote
Many a Shimano brake will get squeaky after months of not being used. Not sure what causes it but have experienced it on more than a few sets. Either a little weaping at the seals or oxidization of the pads, or both.

Regardless I've been able to fix each one

Pop the pads out, torch for 45 seconds (each pad) with a propane torch, gentle sand, clean rotor. Re-bed. Good to go.
flag MustRideAllTheTrails
O+
Posted: Oct 11, 2021 at 17:16 Quote
I haven't seen you say that you have bled the brakes. I had a similar issue and it turned out to be a bad bleed job. I guess there was a small air bubble which meant the pads weren't gripping with enough force, which caused them to squeal and glaze the pads.

I re-bled them and it finally fixed my issue.
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