Squealing brake solution needed

[Topo]

The front disc screams terribly on both our KBO Breeze bikes. Very weird since the rear one is fine. I've changed pads, used some metal sand paper on the rotor, but nothing will quiet these things down.

They are mechanical brakes, so I tried swapping with an xtech cable pull hydraulic unit, but there's something wrong with it and takes a massive force to get even a little stopping power. It's not spongy, as if it needs fluid or bleeding. It's just impossible to squeeze hard enough to get any stopping power. I was gonna try to bleed it, but I think it has some other issue.

KBO said I need to change out the rotor, but I'm having trouble believing that will solve the problem. I don't see any blems or visual problems with the rotor and think it's a waste of money to simply swap it out with an exact replacement. How is that gonna help? Anyway, would appreciate some assistance figuring this out. It's crazy annoying how deafening the screeching is. Thanks for any help figuring this out.

 

[Annieolnie]

I think KBO is right. Take your rotor off and sight along it, or see how it lays flat. It is probably out of true. You don't have to buy their rotor, any rotor you like with that bolt pattern and diameter will work. I'll post a pic of the breeze rotor to make it easier for you to hunt for one.

 

[Nighted]

there's something wrong with it and takes a massive force to get even a little stopping power

That's definitely not normal and excessive force can break the bladder which can be replaced ... if you can find one. Possibly you'll have to purchase a new lever.

 

[Topo]

I think KBO is right. Take your rotor off and sight along it, or see how it lays flat. It is probably out of true. You don't have to buy their rotor, any rotor you like with that bolt pattern and diameter will work. I'll post a pic of the breeze rotor to make it easier for you to hunt for one.View attachment 20382View attachment 20383

Thanks…the one detail I forgot to mention is that the loud squealing happens only when I apply the brakes. It doesn’t seem to be warped, as I far as I can see, but I have have not removed it and put it on a flat surface. I can look down as I’m riding and don’t see it wobbling. That’s why I’m hesitant to look at a replacement as a solution. Unless there’s some sort of structural issue with the rotor that makes it generate the intense vibration squealing, I’m unsure a new one would help.
I will say that there was far less of the problem when I first put the hydraulic brake on. With it squeezing the rotor from both sides, unlike the one side the mechanical brake does, that might be a clue, but I don’t know what it might be.

 

[Unit59]

My bike had just the front making noise and I cleaned the rotor with alcohol and a clean cloth and it solved the problem, it must have picked up some oil from the road.

 

[Topo]

My bike had just the front making noise and I cleaned the rotor with alcohol and a clean cloth and it solved the problem, it must have picked up some oil from the road.

That’s something so basic that I have not tried. Thanks…gonna give it a shot today.

 

[Mysery]

I had noise when using my mechanical brakes when I first got my bike. The gap between the inside pad, which does not move when the brake is applied, was too wide and was causing the rotor to bend. I adjusted the bracket that holds the brake assembly so the gap between the non-movable pad was about .002/.003 of an inch.

 

[JerryB]

My bike had just the front making noise and I cleaned the rotor with alcohol and a clean cloth and it solved the problem, it must have picked up some oil from the road.

Yep...worked for me too.

 

[neutron]

I bought those XTECH calipers too. One failed completely and I never though they were better than mechanical calipers that came with the bike. I replaced the failed hydraulic caliper with the original take off and am happy with the results. I clean my rotors with acetone.

 

[Topo]

I had noise when using my mechanical brakes when I first got my bike. The gap between the inside pad, which does not move when the brake is applied, was too wide and was causing the rotor to bend. I adjusted the bracket that holds the brake assembly so the gap between the non-movable pad was about .002/.003 of an inch.

Is it obvious how to make that adjustment? Is it something different than holding the brake lever in when tightening the brake caliper assembly into position?
Sounds like something I should do even if cleaning the rotor helps.

 

[Mysery]

Is it obvious how to make that adjustment? Is it something different than holding the brake lever in when tightening the brake caliper assembly into position?
Sounds like something I should do even if cleaning the rotor helps.

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• #20

I had an intermittent squeaking noise from my front brake while riding that if applied the front brake momentarily would stop the squeak for awhile. It started happening more often so I finally decided to check it out. This is on a mechanical disc brake setup. On my setup the inboard pad is fixed while the outboard pad moves in to apply pressure. While applying the brake I noticed that it was pushing the disk toward the wheel about .100 / 2.54 mm., not good.
I checked the disk / rotor for run out and there was none. Took the caliper off and everything looked good. I did notice that the screws had been installed with blue loctite from the factory. When I put it back together I adjusted the caliber / bracket to have a gap between the inboard pad and disc of about .0015 / 0.0381 mm. The outboard pad has a gap of .010 / 0.254 mm. The brake works great with no noise. Because I can I decided to safety wire the caliper mounting screws.

 

[Zincalo]

That’s something so basic that I have not tried. Thanks…gonna give it a shot today.

Even better get a can of brake cleaner from a motor spares shop, it's made for the job. Clean the pads too if you are not replacing.

 

[Annieolnie]

Be careful with the brake cleaner, it can also strip paint.

 

[Zincalo]

Be careful with the brake cleaner, it can also strip paint.

Are you sure you're not thinking of brake fluid, ? Car stuff will strip paint, also highly flammable. I've not had a problem with automotive brake cleaner in 35 years.

 

[HumanPerson]

i've seen painted strippers

 

[Topo]

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• #20

I had an intermittent squeaking noise from my front brake while riding that if applied the front brake momentarily would stop the squeak for awhile. It started happening more often so I finally decided to check it out. This is on a mechanical disc brake setup. On my setup the inboard pad is fixed while the outboard pad moves in to apply pressure. While applying the brake I noticed that it was pushing the disk toward the wheel about .100 / 2.54 mm., not good.
I checked the disk / rotor for run out and there was none. Took the caliper off and everything looked good. I did notice that the screws had been installed with blue loctite from the factory. When I put it back together I adjusted the caliber / bracket to have a gap between the inboard pad and disc of about .0015 / 0.0381 mm. The outboard pad has a gap of .010 / 0.254 mm. The brake works great with no noise. Because I can I decided to safety wire the caliper mounting screws.

I see you drilled hole into the caliper bolts, or maybe there was already a hole in them? My caliper definitely pushes the disc with the same one sided pressure. I’ll have to see about adjusting it when we return from our trip. Thanks

 

[Annieolnie]

Are you sure you're not thinking of brake fluid, ? Car stuff will strip paint, also highly flammable. I've not had a problem with automotive brake cleaner in 35 years.

I have, so has Smaug. It is also not very friendly with plastic cabling. You can spray it on a paper towel and be watchful of it, but I wouldn't spray it right at the bike. I have a feeling brake cleaner over there may be a bit different from brake cleaner over here.

 

[biknut]

Mechanical brake noise is typically caused by the fixed inboard pad being too far from the rotor.

 

[Topo]

Mechanical brake noise is typically caused by the fixed inboard pad being too far from the rotor.

Is the solution to adjust the caliper assembly, by loosening the 2 mounting bolts and positioning it differently?
I’ve always depressed the brake lever and kept it held before tightening the bolts. Is there a better way to adjust it? How do you decrease the distance from the fixed pad, accurately?
Thanks

 

[biknut]

The adjuster for the inboard pad is a screw on the inboard side of the caliper. Start out by loosening the cable adjuster and retracting the inboard pad all the way. Next adjust the inboard pad adjuster back in about 1 turn. Next position caliper so the inboard pad lightly touches the rotor, and tighten the caliper bolts. Now with the wheel off the ground retract the inboard pad just enough to stop touching the rotor and no more. Now you can adjust the outboard pad to the amount of lever play you prefer.