Front brake not working and sounds like a fog horn!! Fixed!

JayMartin333

Spoke about this in another post but thought I'd post in here, Its a Tektro Novela mechanical disc brake, dual pad angle adjust, post mount, 160mm rotor (Specialized website spec) it hasnt worked since I got it so no idea what it is, took it apart today cleaned the disc and the pads and its got worse

Video is more for the noise than anything, looks like it stops it but I was only doing about 0.0000000002mph!



(ignore the tyre on backwards, have changed that the right way round!)

nicklouse

Have you read the topics covering this in the FAQs above?
Poor set up.NAND some just make noise. Seem to work fine so not contamination ( or not bad contamination).

JayMartin333

It doesn't work fine though, works really really badly

bennett_346

What did you clean the discs with?

nicklouse

JayMartin333 wrote:

It doesn't work fine though, works really really badly

From the flex in the fork I would say they are working.

But as above what has been near it?

tbikeradar

great sound i love it. who needs a horn

The Rookie

Noise sounds perfectly normal for cheap brakes with a chap fork, it's rarely the brakes that cause the noise but everything else allowing stuff to vibrate.

Hard to judge how good or bad they are, compared to V-s they won't be as good.

YeehaaMcgee

bennett_346 wrote:

What did you clean the discs with?

+potato.

cooldad

YeehaaMcgee wrote:

bennett_346 wrote:

What did you clean the discs with?

+potato.

I tried potato, doesn't work.

JayMartin333

Ok yeah it works at a slow speed, but anythin worth braking from it doesn't my old bike used to send me over the bars an that had cheap brakes do doesn't explain it, washed it with water and a fine sanding block same with the pads!

JayMartin333

I washed te bike with soap before this could this not help the situation?

The Rookie

What soap, anything that leaves a residue is not a good idea!

JayMartin333

Cleaned the brakes with brake disc cleaner and a light sand paper back is spot on now, just a slight squeek, front stops on a dime now ive adjusted it with the pad adjuster and cleaned it, still squeeks like a bitch tho, gonna get a slightly more coarse sand paper and have another go at the pads failing that, new pads!

Bought new Shimano discs too and theyve sent the wrong ones out, the ones they've sent look like they need to fit into a spline?? Mine are just 6 torx bolts

The Rookie

Shimano use the centrelock fitting or 6-blt, sounds like YOU BOUGHT the wrong ones....

I doubt with those forks you'll ever loose the noise, it's too low a frequancy to be the disc making the noise....

steelie600

I have donned my flame proof jacket and am prepared for a flaming.

HOWEVER I am a motorbike mechanic by trade and squeaky brakes are my bread and butter.

Have you used brake pad lubricant on the surfaces where the pads touch the CALIPERS (not the disc) Coppaslip is what you want for this, use sparingly

Is the pad return spring worn??

Have the pads glazed through getting TOO hot?? If they have you want a hotter heat range pad, move to sintered and above to cure the heat issue

Is the disc contaminated with shock oil/brake fluid

Have you got brake fluid or shock oil on the pads

steelie600

Just noticed the mechanical caliper bit in the op, in this case are the caliper pivot bearings worn??

YeehaaMcgee

steelie600 wrote:

touch the CALIPERS (not the disc) Coppaslip is what you want for this, use sparingly

If you're prepared for a flaming, then you must know why it's bad advice right?

For the others... Car/motorcycle brakes reach very high temperature, which means they can burn off any residual grease that migrates onto the pad material.
See, the pads are porous, and copperslip grease can (and ultimately will) find it's way onto the friction material.
A well set up MTB brake system will not, under any circumstances benefit from copeprslip, nor will it need it.

steelie600

And if your hammering your MTB brakes they will reach similar temeratures!! If you note I said sparingly in my post and seeing as coppaslip is more COPPER than grease I cant see an issue tbh. I stand to be corrected like, BUT in my experience any brake that is squealing is caused by the pads VIBRATING in the discs and in the calipers. Coppaslip CAN in some circumstances cure this.

Surely to god it cant help to try, and if your a savvy mtb spanner jock youd have coppaslip in your toolbox for threads etc any ways!! SO you can nick a small amount to try it!!

I personally think he's cooked the pads though, but again I stand to be corrected

steelie600

Second degree burns caused by push bike brake disc!! Dont get hot eh???

YeehaaMcgee

steelie600 wrote:

And if your hammering your MTB brakes they will reach similar temeratures!! If you note I said sparingly in my post and seeing as coppaslip is more COPPER than grease I cant see an issue tbh. I stand to be corrected like, BUT in my experience any brake that is squealing is caused by the pads VIBRATING in the discs and in the calipers. Coppaslip CAN in some circumstances cure this.

The thing is, preventing the vibration is far better than just acoustically hiding it, which is waht copperslip does.

steelie600 wrote:

Surely to god it cant help to try,

Exactly.

Have you got a non contact thermometer to hand? Try measuring the difference between a car/motorcycle brake disk being used, and a mountain bike brake disc. You'll find there'll be a considerable difference in operating temperature.

steelie600

I can tell you under normal road use motorbike brakes run at around 150*c and cars about 180*c. But just remember the weight difference and size difference.

I do beleive tho that youll get MTB brakes well over 200*c if your pushing on, if not hotter.

On my race bikes (I used to race motorbikes 1000cc v-twins) I had my brakes to about 500*c and Carbons on Moto GP are about 1200*c :shock:

Ill agree with you that its just masking the situation, and in an ideal world its not needed. I was only giving a suggestion to help with the squealing!

Twelly

steelie600 wrote:

Second degree burns caused by push bike brake disc!! Dont get hot eh???

Haha, please tell me you went away and burned yourself just to prove your point...

YeehaaMcgee

You'd have to be really caning the brakes to get them over 200degrees, like dragging them down an alpine run. At which point, you will have boiled them to the point of damage already.

How about some real-world experience then? Plenty of us here have tried the copperslip method, and found it to not solve the problem. Even if the noise goes away, not only are you risking contaminating the pads, but you're also just hiding the cause of the vibration, not actually curing it. So the brake performance won't increase.

I've grown tired over the years of hearing people's claims about how to cure, clean, revive, fix, or maintain their brakes, and every single one of them has had brakes that I would consider sub-par.

YeehaaMcgee

steelie600 wrote:

Second degree burns caused by push bike brake disc!! Dont get hot eh???

Yes, we know that the brakes get hot, that's not in dispute. It's actually how the brakes work.
Now, what was your point?

steelie600

No my mate did it on his last year, but couldnt find the pic, thats from a quick google search!!

steelie600

YeehaaMcgee wrote:

You'd have to be really caning the brakes to get them over 200degrees, like dragging them down an alpine run. At which point, you will have boiled them to the point of damage already.

How about some real-world experience then? Plenty of us here have tried the copperslip method, and found it to not solve the problem. Even if the noise goes away, not only are you risking contaminating the pads, but you're also just hiding the cause of the vibration, not actually curing it. So the brake performance won't increase.

I've grown tired over the years of hearing people's claims about how to cure, clean, revive, fix, or maintain their brakes, and every single one of them has had brakes that I would consider sub-par.

I fully agree with what you are saying, except the risk of contaminating the pads. IF applied correctly there isnt an issue. But thats only my opinion, not like i've got qualifcations in it or owt.

My own personal opinion in this guys squealing issue is the pads have glazed and are fit for fileing, under B 1 N

I also have a non contact thermometer in my toolbox and in the interest of science, im gonna wait at the bottom of Llandegla next time my mates go (Ive still gotta build my bike) and get some brake temps, cos youve got me interested now

Chunkers1980

Fluid boiling temp is pretty much fact.

YeehaaMcgee

steelie600 wrote:

I also have a non contact thermometer in my toolbox and in the interest of science, im gonna wait at the bottom of Llandegla next time my mates go (Ive still gotta build my bike) and get some brake temps, cos youve got me interested now

That would be pretty cool, because in a geeky way, I am genuinely interested in what it would show. I used to have tools like that in my old job, but alas, since moving jobs, I have since thought of a load of fascinating things to do with a range of peculiar tools.

I'd also be interested in the difference between Shimano's heatskink-ed brakes, and say, an Avid setup. The XTs I have now are certyainly the most fade-resistant brakes I've ever had.

steelie600

YeehaaMcgee wrote:

steelie600 wrote:

I also have a non contact thermometer in my toolbox and in the interest of science, im gonna wait at the bottom of Llandegla next time my mates go (Ive still gotta build my bike) and get some brake temps, cos youve got me interested now

That would be pretty cool, because in a geeky way, I am genuinely interested in what it would show. I used to have tools like that in my old job, but alas, since moving jobs, I have since thought of a load of fascinating things to do with a range of peculiar tools.

I'd also be interested in the difference between Shimano's heatskink-ed brakes, and say, an Avid setup. The XTs I have now are certyainly the most fade-resistant brakes I've ever had.

I can see a test sesh coming on!! LOL!!

And who ever said about brake fluid boiling point..............

Dry boiling point Wet boiling point
DOT 3 205 °C (401 °F) 140 °C (284 °F)
DOT 4 230 °C (446 °F) 155 °C (311 °F)
DOT 5 260 °C (500 °F) 180 °C (356 °F)
DOT 5.1 270 °C (518 °F) 190 °C (374 °F)

and theyre the MINIMUM for the standard. I use castrol race spec in my race bikes with a boiling point of typically 320°C and thats dot 4!!

YeehaaMcgee

Yes, but most brakes are porrly setup and contain a fair amount of water, remember

nicklouse

YeehaaMcgee wrote:

You'd have to be really caning the brakes to get them over 200degrees, like dragging them down an alpine run. At which point, you will have boiled them to the point of damage already.

boiled with discs at that temp?

some brakes maybe most i think not.

had my Codes up too about 300C according to the temper chart. no boiling but the brakes were crap.

the next year went the Ones and no issues.

Oh
and Yes Swedish big hills

a good thing to remember is the steel temper colour chart as it gives a quick reference.

eg