noisy brakes

[gr1976]

The squealing (when braking) on my cb750 is getting out of control. I've reset the clearances between the pad and rotor, lubed the hinge pin, caliper was rebuilt last year and in good shape, and I've filed the pads (which will shut it up for a few rides).

Any one know if I can have the rotor turned to knock the glaze off it and where? Any other ideas? I have a feeling my generic pads aren't helping, anybody know.if a better pad will help?

[cb500bobber]

It very well could be the pads if you can't turn the rotor but I have a rotor that came off my cb500 I don't know if they are the same but let me know if you want to try that

[indyfour]

I had the exact same problem on my '74 CB550. The brake would squeak all the time regardless of what I did. Finally I decided to drill the rotor. I had read about others doing it with good results, so I gave it a shot. I found a pattern online for the 550 rotor and did it myself. I have had not one single squeak since drilling last year and brake feel also seems to have improved slightly.



There's also a guy over on the sohc4.net forum who does a drilling service for $40. You ship him you rotor and he ships it back drilled and chamfered. IMO, $40 is a great deal considering you probably spend at least half that on decent bits to drill holes yourself...and then there's the billions of razor sharp metal spirals you have to clean up after you're through. Let me know if you want me to post the link for his service.

[gr1976]

Pat - thanks for the offer but I am going to try and fix what I have

Indyfour - that sounds like a good idea I'll give it a shot. I'll do it myself. Do you have a link for the templates?

Thanks

[indyfour]

The links to the PDF templates should appear on the first post of this page...

forums.sohc4.net/index.php?topic=45389.0;nowap

I printed the template and resized it several times to get a good fit, cut it out and taped it onto the rotor....then used a spring-loaded center punch to mark all the locations. Takes a while to drill all of the holes out on a press, but it's not rocket science. There also seems to be a debate on whether or not to chamfer the holes....I chose to do so and used a cheap 45deg bevel bit. I also chose to repaint the cast center part of the rotor while it was off and also lightly resurfaced the faces of the rotor with a sander.

Happy drilling!

[dannyboy]

I will preface this post by saying this is a real nerdy response, but then I am a nerdy mech engineer...The cross drilling will definitely help the brake feel and noise for a few reasons:

1. The holes will eliminate the noise because the brake will no longer have a constant and steady force applied to it and cause resonance in the rotor(i.e. the squeaking) In addition, the holes will change the natural frequency of the rotor. This usually pushes it out of the range of usage.

2. The holes create an area where the pad must start the friction path again creating higher localized friction and increasing stopping power. (This is why furniture is easier to move once it is moving and stopping to rest just creates more work)

3. The holes clean the brake pad off and give it a fresh surface to start with. This prevents debris from getting in between the pad and the rotor and not causing a good friction surface.

I am sure there are other reasons if you keep digging and you are really interested. I felt the need to explain some of the science for others who are contemplating the change.

And your trip to nerdville is now over.

[leadkrm]

Cool I'll be using the drill press on this project

[tango911]

also, squeeks are caused bye vibration, thats why many mech's use the blue greasy stuff on the back side of the pads to lessen the vibration. The hole drilling is a good idea. it will make your front brakes grab better. Ill prob do that to mine as well.

[gr1976]

thanks for the links...I'm definitely heading down this route as soon as I get caught up on some other projects. Was out riding last night and the damn rear let out a few squeals.

Guess I'll have to drill the drum as well....maybe I'll just clean it first.

[novafrk]

Aug 2, 2011 9:31:36 GMT -4 dannyboy said:

I will preface this post by saying this is a real nerdy response, but then I am a nerdy mech engineer...The cross drilling will definitely help the brake feel and noise for a few reasons:

1. The holes will eliminate the noise because the brake will no longer have a constant and steady force applied to it and cause resonance in the rotor(i.e. the squeaking) In addition, the holes will change the natural frequency of the rotor. This usually pushes it out of the range of usage.

2. The holes create an area where the pad must start the friction path again creating higher localized friction and increasing stopping power. (This is why furniture is easier to move once it is moving and stopping to rest just creates more work)

3. The holes clean the brake pad off and give it a fresh surface to start with. This prevents debris from getting in between the pad and the rotor and not causing a good friction surface.

I am sure there are other reasons if you keep digging and you are really interested. I felt the need to explain some of the science for others who are contemplating the change.

And your trip to nerdville is now over.

I don't think you'll get called a nerd on this site. Too many gearhead / garage engineers for that. :-) I wish my bike had squeaky discs so I could do this mod... I'm dealing with high tech drums!