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Message started by Gyrobob on 06/21/13 at 06:44:20

Title: Brake Squeal Cure(s)
Post by Gyrobob on 06/21/13 at 06:44:20



Brake squeal is something that can be controlled rather cheaply.

The squealing is from a resonance of high frequency vibrations in the pads/calipers when they contact the rotor.  Because of the job the disc brake has to do, this squeal is common, even though the manufacturers' engineers probably tried hard to prevent it.

There are lots of ways to fix this.  Replacing pads with lots of material left on them is not a sensible option,… a waste of money.

The idea is to change the resonance of the parts that vibrate, thereby pushing the resonance out of the range that creates a squeal.  Here are some ways:

 -- Simply wash the rotor and brake pads.  Get them REALLY clean.  If it works, it will probably have to be done occasionally to keep the squeak away.

 -- Use the lube typically supplied with replacement pads.  This is a high-heat lube that goes between the pads and the piston that changes the resonance frequency.  Use sparingly.

 -- Use that same lube on all the parts that support the caliper, allowing the caliper to move back and forth.  Clean everything really well first, and, again, use sparingly.

 -- I hear folks like Loctite, Permatex, CRC, etc., have sprays/pastes designed to fix the squeal, as well,... apply to the back of the pad, methinks.

 -- Sometimes the pads, or even the rotors, can acquire a glaze that tends to make a squeal.  Lightly scouring one or both surfaces can help here.  Use 400 grit sandpaper (wet), or rubbing compound, steel wool, chore girl, comet cleanser, etc.  You don’t want any scratches, just a satin finish. You might have to do this every few thousand miles with a particular combination of rotor and pads.

 -- Chamfer the edges of the pads just a little, maybe a 1/16" wide chamfer.
        --- Chamfering the leading edge of the pad is sufficient.    
        --- This alters how the leading edge of the pad tries to "dig in" to the rotor, changing the resonance frequency.
        --- The squeal may come back in a few thousand miles as the pads wear down. Just chamfer it again.

 -- Clean all the surfaces completely, then put a very thin layer of RTV on the back of the pad where it contacts the piston in the caliper.  Also put a very thin layer on the surface of the piston that contacts the pad.  Let it dry for a few hours before reassembly.  
        --- Very thin layer = Put a little on your finger, rub it on the surface, then wipe just about all of it off with a clean finger.  
        --- You don’t want any actual cushion here,…. that will make the brakes feel spongy.  You want only enough to change the resonance of these two mating surfaces,.. just residue, not an actual layer.  
        --- Use something with a high heat capability.  Normal RTV works,.. hi-temp RTV might be better.  It's cheap.

 -- Cut out a piece of coke can metal shaped like the back of the disc brake pad, and insert that piece between the pad and the piston.  That metal is thin but is pretty tough stuff -- I use it for shims when aligning gyrocopter rotors.  Sounds goofy, but it does change/negate the resonances, so it can eliminate the squeal.
 
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Title: Re: Break Squeal Cure(s)
Post by verslagen1 on 06/21/13 at 07:30:00

And if that don't work, wash with soap and water.

And if that don't work, heating them up by braking hard a few times.
Drive off all the moisture, works for the back too.

And if that don't work, try getting the disc drilled.

And if that don't work, think of it as an enunciator "Hey, I'm braking here" or "get outta my way"

Title: Re: Brake Squeal Cure(s)
Post by TG on 06/25/13 at 16:11:07

I can always expect a clear and "down to earth" answer from verslagen! I find myself laughing most times, too.

Title: Re: Break Squeal Cure(s)
Post by Gyrobob on 07/24/13 at 07:00:37


465542435C5157555E01300 wrote:
And if that don't work, wash with soap and water.

And if that don't work, heating them up by braking hard a few times. Drive off all the moisture, works for the back too.

And if that don't work, try getting the disc drilled.

And if that don't work, think of it as an enunciator "Hey, I'm braking here" or "get outta my way"



"And if that don't work, wash with soap and water." Good idea,.. works every time,.... until they get dirty again.  Maybe as a preflight checklist, we could include washing the rotor before start up.

"And if that don't work, heating them up by braking hard a few times. Drive off all the moisture, works for the back too."  This might work well, too, depending on the actual surfaces, temps, humidity, dirt, age, etc.,... until the brakes cool off again,.. which they will do after a few minutes of either riding around, or being parked.  Maybe we could use a crystal ball to predict when the brakes are about to squeak, and we could then lightly apply the brakes for several seconds ahead of time to heat them up.

"And if that don't work, try getting the disc drilled." Too pricey for me.

"And if that don't work, think of it as an enunciator "Hey, I'm braking here" or "get outta my way" " In this day and age of airconditioned, 2,000 watt stereo system cages, I doubt this would be very reliable.

Title: Re: Brake Squeal Cure(s)
Post by verslagen1 on 07/24/13 at 07:10:48

Do you know why there are lot's of ways to fix brake squeal?

...they don't always work.

my methods work and will get you from...
" I gotta fix this now " to " I can last till I need new pads "

Title: Re: Brake Squeal Cure(s)
Post by Gyrobob on 08/20/13 at 07:32:23


706374756A6761636837060 wrote:
Do you know why there are lot's of ways to fix brake squeal?

...they don't always work.

my methods work and will get you from...
" I gotta fix this now " to " I can last till I need new pads "




Yes, your methods work, as do mine.  They aren't "mine" anyway.  I didn't invent them,.. they are just some techniques other more knowledgeable guys let me know about over the past half-century of two wheeled living.

No point in suppressing any of them, eh?




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