Gyrobob
Serious Thumper
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Posers ain't motorcyclists
Posts: 2571
Newnan, GA
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If all you want to do is stop the squeal, try these ideas. Using these techniques, I have stopped every squeal I ever had in cars and motorcycles. (from something I posted last year)
------------------------------ 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 Suzuki engineers probably made a large effort to prevent it.
There are several things to try. Replacing pads with a lot of material left on them is usually not a sensible option,… just a waste of money.
The idea is to change the resonance of the parts that vibrate, therefore pushing the resonance out of the range that tends to create a squeal. Here are some ways:
-- 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 that allow the caliper to move back and forth. Again, use sparingly. -- 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. -- Chamfer the edges of the pads. --- This changes the angle between the edge of the pad and the rotor surface, which changes how the pad tries to "dig in" to the rotor. --- Chamfering the leading edge of the pad is sufficient. This will change the resonance frequency one way or another. --- If chamfering the leading edge stops the squeal, it may come back, say, 4,000 miles later when the pads wear down enough to erase the chamfer. Just chamfer it again. -- Clean 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. --- By "very thin layer” I mean 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. --- Make sure you use something with a high heat capability. Normal RTV will work,.. 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 pretty tough stuff,... thin, but tough. I also 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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