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Falcifer

Joined:

Sep 10

Posts: 11

Falcifer says:

Squealing Brakes

I know there's a few threads up already about this issue but I'm having real problems!


I have a CBF600 that's done about 20K miles. The front brakes squeal very loudly when coming to a stop, maybe under 15mph, in most conditions. By very loudly I mean really loudly!

I took it to a garage and the guy said a disc was warped. He managed to stop it temporarily by cleaning the dust off everything but this lasts only a short time. I can't afford new discs- can I have them machined or is there another solution?

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  • Posted 4 years ago (12 June 2011 15:48)

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jaffa90

Joined:

Mar 09

Posts: 8820

jaffa90 says:

squeal

Warped discs should be replaced and not machined,if not replaced they will shave your pads away.I hope your calipers are free to float and the pistons are free and the pads as well with their housings lubed.

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hairybob

Joined:

Jan 09

Posts: 483

hairybob says:

warped disc

if you have a warped disc you should feel it snatch at low speed and possibly pull steering around depends how bad it is, run out service limit is about 0.3mm, the only way to be sure is to measure it or get someone to check it for you, also calipers as these are probably sticking or siezed, unless you have obvious damage from an impact ie forgotten disc lock. I had a slight warped disc failed mot, tester could see it on his brake meter.  

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hairybob

Joined:

Jan 09

Posts: 483

hairybob says:

ps

it ain't worth trying  to machine discs you only have about 0.5mm wear limit . Don't forget new pads as well as discs.

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Dabbsy

Joined:

Aug 02

Posts: 488

Dabbsy says:

squealing brakes

As well as cleaning the dirt off, did he get the disc mounting bobbins free of crud? They allow the discs to centre more easily and could help. Otherwise, it is new disc time.....

Chris

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sgom

Joined:

Jan 11

Posts: 12

sgom says:

noisy brakes

before you go spending any money try a little smear of copper oxide paste on the back of the pads

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def1938

Joined:

Aug 11

Posts: 11

def1938 says:

brake noise

Yes, some copper anti-seize. Perfect!

Just be careful not to get any on the friction surfaces.

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smoto5

Joined:

Mar 09

Posts: 4548

smoto5 says:

This sounds like it could be

glazed pads or discs, possibly caused of course by the calipers sticking if they are sliding type, or possibly by the pistons sticking in the calipers, although that depends on age and operating conditions to a certain extent. So leaving aside that for the minute, cheapest and most effective thing to start with would be to abrade the braking surface of the disc with coarse grade emery paper/sandpaper/aluminium oxide paper, working at 90 degrees to direction of rotation or in small circular motion, this would help the brake pads to bed back in properly, to test if your brakes are dragging or sticking, you need to get the front wheel off the floor, either by something under the front of the bike, front paddock stand, wooden blocks, leaning it against side stand with somebody holding back down so wheel comes off floor etc. (make sure it is secure and safe!!) You can get get a rough idea pushing bike back and forwards on its wheels but this is a bit more precise, anyway, the wheel should rotate reasonably freely with no dragging, and if you apply the brake gently or hard, the wheel should still rotate easily after  releasing. If not the brakes may need an overhaul to free everything off. It's also worth noting as above that brake pads should be free to move easily, corrosion on the actual pad edges can stop this happening, the rust would need to be removed if so, also a similar deglazing process can be used on the pads braking surface as used on the discs, organic and asbestos type pads will abrade quicker than sintered metallic type materials, dust mask and damp disposable cloths to wipe off dust are advisable!! take care of your health! :smile

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def1938

Joined:

Aug 11

Posts: 11

def1938 says:

brake pads asbestos

Asbestos...did you say asbestos?:unsure: There had better not be any asbestos in your brake pads.:mad:

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MakemRider

Joined:

Jul 11

Posts: 244

MakemRider says:

Squeal

One thing we used to do with the pads when I was a car mechanic was to put a small chamfer on the leading & trailing edges of friction surface.

Whether this is effictive on pads these days I'm not sure, these day many pads have curved leading & trailing edges as against the straight edges of my days.

The 'copper slip' method does work in many (if not all) cases

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