Noisy Breaks but not pad twitter on the rotors.

[NewtSoup]

My pistons return fine I get no twittering of pads on disks.

However, When I pull the rear brake lever it sounds like I'm grinding metal on metal except I'm not. If I remove the wheel and inspect the pads they have plenty of material on them and they look just like slightly used pads.

Then when I put them back in the rear brake will be silent and brake nicely for the next hour or so and then it slowly goes back to sound like I'm running gravel through it.

I have loosened the two mounting bolts, applied the brake and re-tightened them and this seems to have improved it a a little but not much.

Also If I douse it liberally with disk brake cleaning spray it's silent for a while before going back to the grinding noise.

Any ideas what could be causing this?

 

[soundwave]

i would get some new pads and try that first because once the pad is contaminated its time for the bin.

 

[NewtSoup]

These are actually brand new pads. They've done less than 500miles.

They've been doing it since a few hours after I put them in.

I will replace them again if I have to. It's possible wayward chain lube got on them but would that make them make a grinding noise?

 

[NewtSoup]

Pics of the rotor and the pads in case you can see anything untoward

 

[NewtSoup]

the black on my hands is just brake dust, it's not oily

 

[soundwave]

well they dont look very clean tbh but some rotors only work well with the right compound brake pads it could be thats ur problem.

you could try and give the rotor a clean and a rub with some fine sandpaper but imo you will need new pads.

i got some of these for my bike and they feel the same as you are getting so sat in a draw lol

Uberbike Finned Semi Metallic Disc Brake Pads - Avid XO Trail, Elixir 7 Trail, Elixir 9 Trail

For use with Avid XO Trail, Elixir 7 Trail, Elixir 9 Trail disc brake systems.

www.uberbikecomponents.com

 

[peter.c]

That's quite a lip step on the edge of the disc suspect that's the problem time for new discs

 

[NewtSoup]

The ones I chose were made my Mexital to fit my calipers. I bought the sintered ones as they are supposed to last longer and I do a LOT of miles.

I have found the genuine Shimano pads for my calipers on Amazon. They cost a bit more but probably better.

 

[NewtSoup]

That's quite a lip step on the edge of the disc suspect that's the problem time for new discs

It does look like it doesn't it? But there isn't one, not on either side. just a different shade of polishing by the pad.

 

[NewtSoup]

I've reassembled the bike and put the pads back in - lo and behold the brakes a silent again beyond the normal hiss of pads being applied to disc. It won't last long though

The calipers / brakes are Shimano M315 front and back. 160mm Centrelock Rotors (whatever centre lock means )

 

[soundwave]

Centrelock Rotors are the way they fit to the wheel instead of 6 bolts.

Shimano RT99 Ice-Tech FREEZA CL Disc Brake Rotor | Chain Reaction

Shimano RT99 Ice-Tech FREEZA CL Disc Brake Rotor - Lowest Prices and FREE shipping available from The World's largest online bike store - Chain Reaction Cycles

www.chainreactioncycles.com

 

[Andy-Mat]

My pistons return fine I get no twittering of pads on disks.

However, When I pull the rear brake lever it sounds like I'm grinding metal on metal except I'm not. If I remove the wheel and inspect the pads they have plenty of material on them and they look just like slightly used pads.

Then when I put them back in the rear brake will be silent and brake nicely for the next hour or so and then it slowly goes back to sound like I'm running gravel through it.

I have loosened the two mounting bolts, applied the brake and re-tightened them and this seems to have improved it a a little but not much.

Also If I douse it liberally with disk brake cleaning spray it's silent for a while before going back to the grinding noise.

Any ideas what could be causing this?

It sounds as though you have set them up so that they are rubbing, eg. too tight.
They get hotter and hotter, expanding slightly, and getting hotter faster and noisier.
The next time it happens, lick your finger and see it they are hot!
Cooling them down wit fluid,, simply starts the process again.
Regards
Andy

 

[NewtSoup]

It sounds as though you have set them up so that they are rubbing, eg. too tight.
They get hotter and hotter, expanding slightly, and getting hotter faster and noisier.
The next time it happens, lick your finger and see it they are hot!
Cooling them down wit fluid,, simply starts the process again.
Regards
Andy

mmm not really, once they're noisy they'll be noisy the next day too. It's like their collecting sand in them and runnign it between the pads. I'm starting to think i have a bad pad or two on the back brake and it's slowly breaking down.

Wednesday I will be able to go to halfords and get a pair of shimano pads and I will replace them again

Then if they're still noisy I will see if halfords can fix it.

I can't replace the pads sooner because I lost my bank card and the new one wont arrive until wednesday.

 

[soundwave]

you dont buy things in halfords you steal everything you can lol.

b4 you fit the pads give the rotors a going over with some fine sand paper then clean with isopropyl alcohol fit the pads and find a big hill to bed them in.

 

[cyclebuddy]

The ones I chose were made my Mexital to fit my calipers. I bought the sintered ones

The calipers / brakes are Shimano M315 front and back

I'm pretty sure the rotors supplied for the M315 are marked on the rotor "use resin pads only". Sintered are too hard. Shimano B01S are the original resin, which Halfords sell.

 

[NewtSoup]

I will sand down the rotors tomorrow as I have enough pocket change to get some wet and dry carborundum paper.

I may sand the pads for the hell of it too and get a soft cloth in the caliper to get rid of as much pad dust as possible.

I'd do it now but I've settled into a couple of beers for the evening.

 

[NewtSoup]

I'm pretty sure the rotors supplied for the M315 are marked on the rotor "use resin pads only". Sintered are too hard. Shimano B01S are the original resin, which Halfords sell.

Thank you for that. I will change them both asap.

 

[NewtSoup]

shame because the front are fine and make no noise and are on sintered pads too

 

[soundwave]

it does look like those rotors want resin pads and why it does not feel right esp if you use the rear brake more than the front so there is a lot more heat and thus noise and will then just feel worse.

it does not take very long to heat up a rotor to the point it starts to warp the steal and then it is a never ending battle bending them back in to shape as it allways wants to sprig back to the bent position.



that rotor was so bent it jammed the wheel and the pads were bear metal lol

 

[Nealh]

Look on the outer face of the rotor somewhere it should have resin stamped on the face, M315 set as will all the M xxx series right up to at least M525 will be marked resin and need resin/organic pads. If you want to use sintered/metallic pads buy Shimano icetech centrelock rotors cost about £20, they are secured by a central lock disc the same as a rear cassette.