Topic: Re: '76 Honda CB550F: Constant Disk Brake Squeal!!

[dave500]

I'm afraid you can't sand down the type of rotors (stainless steel) we have...

ive scratched em up with a flapper wheel before,ive also sand blasted them,dont last long though,its a some special hard stainless,in the day selling a new bike with shiney new to the world hydraulic disc brake was paramount,had they been plain cast iron they would work better but look terrible rusty on the showroom floor!

[AwesomeCB]

hose and master cylinder rebuild that stops squeal is a fluke.

Naw.

[dave500]

#$%* im glad you know everthing.

[Deltarider]

I'm afraid you can't sand down the type of rotors (stainless steel) we have...

ive scratched em up with a flapper wheel before,ive also sand blasted them,dont last long though,its a some special hard stainless,in the day selling a new bike with shiney new to the world hydraulic disc brake was paramount,had they been plain cast iron they would work better but look terrible rusty on the showroom floor!

Exactly! It had to look good in the brochure and the showroom. If they only had fitted the Brembo's the Guzzi's had...

[Korven]

This is what worked for me on my cb. it had a squeaking sound until applying the brakes lightly. It had no rolling resistance in neutral like yours did so that might need a rebuild. Copperpaste didnt work for me (was alu there from previous owner) Ive heard the Sound comes from microvibration, 6 layer rubber/glassfiber should remove these vibrations. Not much international info about these seem to be found but must be other manufacturers for similar products.

[Deltarider]

Although I did notice after a ride on the fresh pads that only the front half of the pad was worn, like it may be hitting the disc at an angle. I know on bicycles this is actually done on purpose to avoid squeal, but maybe that’s different on motorcycles?

That could very well be it. I remember that on my Koga Miyata Terraliner, a hybrid bike, I used to fit the V-brakes so, that the front part would contact the rim first. I did this on purpose, after I had learned in a bicycle workshop that that would make your brakes screech and it did. I admit I was very childish.

[przjohn]

Here is what has worked for me on a few vintage bikes including H model Kawasakis that are notorious for brake squeal. As has been stated, chamfer a 45 on the leading edge of the pads. The leading edge is actually the back of the brake pads as that is what comes in contact with the disc first. Then, with doubled up hacksaw blades, cut a line through the center of the pad in parallel with the road surface. Don't cut all the way through to the metal just about half way. Then use brake quiet on the back of the pads. Finally, with a very small amount of grease apply a thin coat to where the movable pad slides against the metal caliper. If you want to kick it in the ass send the disc out to True Disc for drilling and grinding. I guarantee your squealing problem will be gone. Below is a pic of the front disc of a 76 750F I restored a couple of years ago. This disc has about 2,000 miles on it since resto and you can see the line that is from the parallel to the ground cut on the pad will leave on a freshly ground disc. You normally will not see this line unless you have your disc ground, it doesn't show on discs that are not ground fresh. It does not affect braking at all as far as I can tell.

 

[andy750]

Everyone who has owned a Honda SOHC has an opinion on brake squeal so Ill give mine . I have two CB750s and have had them for over 20 years. Fixed that nasty squeal two ways: drilled disks, stock pads and Corning High Temp silicone grease behind the pads (with the white o-ring present). This worked, and continues to work for me -the silicone grease has to be reapplied about once a year and it solves the squeal everytime - at least for me. I tried cutting the pads, new brake lines etc but it was the Corning silicone grease that worked for me -when you get it right you will enjoy the bike so much more!!

Good luck!
Andy

[Deltarider]

Everyone who has owned a Honda SOHC has an opinion on brake squeal so Ill give mine . I have two CB750s and have had them for over 20 years. Fixed that nasty squeal two ways: drilled disks, stock pads and Corning High Temp silicone grease behind the pads (with the white o-ring present). This worked, and continues to work for me -the silicone grease has to be reapplied about once a year and it solves the squeal everytime - at least for me. I tried cutting the pads, new brake lines etc but it was the Corning silicone grease

I'm with you, but I fail to see what drilled disks have to do with it.

[RAFster122s]

The Corning Silicone grease is High Vacuum Silicone grease referred to as Petcock grease (chemistry). It works well and does not move or migrate to other areas at high temp.