Author Topic: Squealing brakes have me howling mad! (Read 9724 times)

FunJimmy · « **on:** July 17, 2010, 08:44:25 AM »

What gives?

The brakes on my CB550F where great (although sticking) when I bought it, but the caliper was needing a rebuild to prevent brake drag.

So I pulled the caliper apart, cleaned and powder coater it and rebuilt with a new seal and one of Kevin’s phenolic pistons.
I even installed a full length braided line to help improve braking performance, but on the very first ride the brake squeal was so bad that it rendered the front brakes useless.

That night when I got home I searched the forum for a solution and found several suggestions. As a result, I chamfered the leading edge of the brake pads, sanded any glazing off the disc and pads and used brake squeal stop compound on the backs of the pads.

The results were better, but the squealing is still awful at speeds under 15 miles per hour. That’s at pretty much every light along my favorite bikini watching stretch of road.

Now you wanna get their attention, try these howling brakes. Just too bad it’s not good attention.

All I can think of now is to cross drill and surface grind the rotors. Does cross drilling the rotors help to cancel brake squeal?

Anyone have any other solutions to this annoying problem?

Thanks
FJ

ev0lve · « **Reply #1 on:** July 17, 2010, 09:14:12 AM »

It looks like the 550 has the same basic setup as the 750. I've got the same issue and have tried just about everything EXCEPT there's a thread on here somewhere where someone noticed that the pivot pin for the caliper arm had worn and would allow enough motion that they shimmed it (somehow).

I'll see if I can dig that up.

Edit: Can't find the thread I think I remembered but there are lots of folks with ideas on the pivot pin.

Wisconsin Jeff · « **Reply #2 on:** July 17, 2010, 09:23:22 AM »

SBS makes a rubber-fiberglass adhesive shim that sticks on the back of brake pads. I have sold these to Harley guys and they do reduce noise.

http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=191268&utm_source=google&utm_medium=cse

Brown Bomber · « **Reply #3 on:** July 17, 2010, 10:12:28 AM »

Mainly I'm just subscribing here, (Since I can't get mine to stop squealing either.) and I'd like to see what really worked best for others.

I have two bikes with factory drilled rotors, and they will squeal occasionally, but nothing like the solid rotors on my Honda's. This tells me it's not the rotors, but the pad/caliper that makes the noise. Most likely the piston side of the caliper, since it has a cavity for the piercing sound to emanate from. (If there is an acoustic engineer among us, please chime in.)

Since pads are cheap, and easy to replace (compared to rotors) I would try cutting a grove in the pads before drilling the rotor. Plus rotors are designed to dissipate heat caused by friction, so drilling a rotor reduces it's heat absorbing surface area, and the rotor will get hot much sooner.

Quote from the FAQ;
“Radical” solutions
1.'Cut' the pads in half. Using a hacksaw, you cut a fine gap into each pad (along the line of rotation of the disc - in other words parallel to the ground) down to the wear level indicator. This will effectively disrupt the harmonics component of the pads and give you 2 slightly smaller pad areas on each side of the disc. It also gives you a brake dust evacuation channel - one of the causes of the noise."

This suggests cutting the grove parallel to the ground, while most modern pads have a grove that runs radial to the axle, though I have seen some that are diagonal.

As usual, I have too many irons in the fire, but I'll try this myself. (As soon as I get around to it.)

BeSeeingYou · « **Reply #4 on:** July 17, 2010, 10:14:56 AM »

I can see the main problem. Those babes hear you coming and cover up thinking "jeez, here comes that pervert on the Honda again." You could try riding by on your bicycle instead at least till you get the brakes fixed.

As far as the other problem I have no idea other than OEM pads instead of cheap after market. How about some pics, of the babes, I don't care about your bike.

Really? · « **Reply #5 on:** July 17, 2010, 10:19:47 AM »

I cut the groove, camfered the edge and 320 gritted the disk wet for a while. No more noise out of Momma's 750. I used cheap pads too.

Had a massive squeal coming out of the back and the pads looked fine. replaced with cheap shoes wet sanded the drum. Nice and quiet now.

754 · « **Reply #6 on:** July 17, 2010, 10:21:20 AM »

Take a look at how straight the caliper swing arm is. Just a thought but it swings in an arc..straight would be ideal, but I am thinking, that at full new components, the angle may be enough to give it more chatter than running straight on.

The curved piece that fits into piston and touches back of pad, make sure its clean and lubed..ie freely moves..

bwaller · « **Reply #7 on:** July 17, 2010, 10:22:14 AM »

Jim, as was mentioned grease the pivot pin and make sure the o-rings are in place, use the original plastic washers behind the pad and why not try glass beading the rotor surfaces.

In the seventies, I tried cuts in the pads and all those ideas but I think the disc itself can become so smooth/polished it might be the biggest culprit.

Kevin400F · « **Reply #8 on:** July 17, 2010, 02:50:40 PM »

Hey Jimmy, sorry to hear about the squealing issue. My belief is that most squealing is typically caused by high-frequency vibration of the piston-side pad, with the noise a result of metal-to-metal contact between the outside diameter of pad and the bore of the caliper.

Try putting a thin layer of HIGH-TEMPERATURE silicone grease on the outside edge of the metal backing piece of the active pad and/or in the caliper bore and let us know of that stops the squeal.

FunJimmy · « **Reply #9 on:** July 17, 2010, 03:50:41 PM »

Quote from: srust58 on July 17, 2010, 10:14:56 AM

I can see the main problem. Those babes hear you coming and cover up thinking "jeez, here comes that pervert on the Honda again." You could try riding by on your bicycle instead at least till you get the brakes fixed. As far as the other problem I have no idea other than OEM pads instead of cheap after market. How about some pics, of the babes, I don't care about your bike.

srust58

LOL! Thanks for the tip. The bicycle idea worked like a charm, but I still need to fool them into thinking I’m in my 20’s.

Quote from: bwaller on July 17, 2010, 10:22:14 AM

Jim, as was mentioned grease the pivot pin and make sure the o-rings are in place, use the original plastic washers behind the pad and why not try glass beading the rotor surfaces.

In the seventies, I tried cuts in the pads and all those ideas but I think the disc itself can become so smooth/polished it might be the biggest culprit.

Brent

I think the rotor surface is a big contribution to the issue too. That’s why I was planning the cross drill & Surface grind.
BTW, what o-rings are you referring to?

Quote from: Kevin400F on July 17, 2010, 02:50:40 PM

Hey Jimmy, sorry to hear about the squealing issue. My belief is that most squealing is typically caused by high-frequency vibration of the piston-side pad, with the noise a result of metal-to-metal contact between the outside diameter of pad and the bore of the caliper.

Try putting a thin layer of HIGH-TEMPERATURE silicone grease on the outside edge of the metal backing piece of the active pad and/or in the caliper bore and let us know of that stops the squeal.

Kevin

I’ll give it a try and let you know how it works out. BTW, the pistons are so sweet.

Brown Bomber · « **Reply #10 on:** July 17, 2010, 07:57:26 PM »

Quote from: Kevin400F on July 17, 2010, 02:50:40 PM

Hey Jimmy, sorry to hear about the squealing issue. My belief is that most squealing is typically caused by high-frequency vibration of the piston-side pad, with the noise a result of metal-to-metal contact between the outside diameter of pad and the bore of the caliper.

Try putting a thin layer of HIGH-TEMPERATURE silicone grease on the outside edge of the metal backing piece of the active pad and/or in the caliper bore and let us know of that stops the squeal.

I've tried that, it didn't help.

andy750 · « **Reply #11 on:** July 17, 2010, 08:17:33 PM »

Quote from: Kevin400F on July 17, 2010, 02:50:40 PM

Try putting a thin layer of HIGH-TEMPERATURE silicone grease on the outside edge of the metal backing piece of the active pad and/or in the caliper bore and let us know of that stops the squeal.

+1 I had the terrible squeak last week after replacing pads (and have drilled rotor). Put some Dow Corning Silicone on the back of both pads and squeak is gone (and mine was very bad!).....have done this every year and it usually lasts all summer if not longer.

good luck!
Andy

bwaller · « **Reply #12 on:** July 17, 2010, 08:21:57 PM »

There should be two o-rings, top & bottom of the caliper bracket to seal that pivot pin.

seaweb11 · « **Reply #13 on:** July 18, 2010, 12:50:06 AM »

I'll add this.
my78K used to squeak in parking lots as well, very irritating. Did a bunch of stuff with no real improvement until I drilled the rotor this past winter. No more squeak

http://forums.sohc4.net/index.php?topic=9900.msg771941#msg771941

mycb750k6 · « **Reply #14 on:** July 18, 2010, 06:37:04 AM »

Did you clean and lube the o-ring and use caliper grease on the piston?

FunJimmy · « **Reply #15 on:** August 03, 2010, 04:49:08 PM »

Finally found the remedy.

Drilled rotors, new EBC pads, caliper grease and braided lines.
They even stop better than before. Bonus!

bwaller · « **Reply #16 on:** August 03, 2010, 06:12:56 PM »

Hopefully that's that!

My 750 is usually quiet, but there is one & only one intersection where they always squeal, WTF. The wife's 550 is set up like your's and it complains more often.

seaweb11 · « **Reply #17 on:** August 03, 2010, 07:18:46 PM »

glad I could help

marty · « **Reply #18 on:** July 11, 2011, 03:44:29 PM »

On a 1976 CB400F

I just coated the back of both front brake pads with high temperature silicone grease after cleaning the parts with brake cleaner. No Squeal!!!!
I had a horrible squeal going on for too long, and I just put up with it because the brake worked fine, but man was it annoying and embarrassing!
I ended up favoring the rear brake because it didn't squeal, so I"ll probably be changing those pads soon.

Thank you for the tip.

socalenduro · « **Reply #19 on:** July 11, 2011, 03:50:54 PM »

squeal is vibration and is usually an issue in alignment of when the pad contact the rotor.
the silicon just masks the issue...
as for how to fix it im as clueless as the rest of you.

marty · « **Reply #20 on:** July 11, 2011, 05:54:25 PM »

I agree, the silicone is just masking the real issue, but it cost me $1.40 to fix as opposed to replacing the pads and rotor, or having the rotor resurfaced.
I replaced the pads earlier and that didn't stop the squeal, I never got around to dealing with the rotor; so I guess I've only temporarily solved the issue, but it's great to have some relief even if it is temporary.

Redrider969 · « **Reply #21 on:** July 11, 2011, 05:55:29 PM »

Not insult intended, but some of these solutions sound like they should only be done after you've drawn an pentagram on the garage floor in chicken blood at midnight during a full moon...

Here's a solution that worked for me. Go to the nearest auto parts store and buy a can of CRC Disk Brake Quiet. Read and follow the directions on the back of the can. I did this about 2 years ago on my 75 CB750 and have ridden thousands of miles with nary a squeak, squeal, howl or moan.

seaweb11 · « **Reply #22 on:** July 12, 2011, 12:28:12 AM »

Do you have to read all the instructions?

good night

dave500 · « **Reply #23 on:** July 12, 2011, 12:38:44 AM »

use silicon sealant on the edges of both pads and sort of glue them into place.

Redrider969 · « **Reply #24 on:** July 12, 2011, 07:21:14 AM »

Good question, Seaweb. Unfortunately, I can't answer your question because, failing to recognize the opportunity for research, I read the directions before I started. Perhaps someone else knows? An alternative approach might have been to follow the advice on the sign hanging in our kitchen that reads "If at first you don't succeed, try doing it like your wife told you."

By the way, years ago, when I had my K0, my engineering college roommate suggested drilling several small holes in the pads and inserting graphite pencil lead, on the assumption that the graphite would provide just enough lubrication to stop the squealing. It didn't seem to hurt the braking any, but it didn't stop the squealing either... Maybe I should have tried the chicken blood at midnight approach. Oh well, that's something I can always try in the future. I'll report on the results.

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Author Topic: Squealing brakes have me howling mad! (Read 9724 times)