Brake problem

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Frank
New Member & Happy To Be Here
New Member & Happy To Be Here
Posts: 8
Joined: Sat Sep 27, 2003 10:04 am

Brake problem

Post by Frank »

Hi all,

I am having a problem with my 80 CBX, which is brake squealing when stopping from low speeds.



When I bought the bike and checked the brakes, the pads looked glased so I have replaced with OEM Honda pads. Used coppergrease, all springs etc. were ok. Have degreased the disks at the same time.



The problem was not fixed. A friend advised me to "soften" the edges from the brake pads, this did not help.



I was advised 2 more options:



- Machining the disks, not sure if this is good as tolerance is quickly reached



- Fitting other (softer) pads.



I want to go for option 2 first. Will be interested to hear if anyone on the board had the same problem, and if fixing different pads made a difference, what make you fitted, tech tips etc.



Having this problem for a long time, any help from fellow CBX-ers on the board will be much appreciated.

E Lee

Brake

Post by E Lee »

I went with the simple method first; few sheets of emery paper and some time to hand sand the discs. This may take a lot longer the first time. Then a good cleaning with brake cleaner.

Not to course a paper and not to fine. It takes the glaze of and all is well. Sand and turn, inside and out. You will see what looks to be nasty scratches but what you see is marks in the glaze. They are hard those discs so had sanding is not going to cause any problems. I touch them up every so often just to keep the glaze in check.

Later,

Ed Lee

Jim-Jim
ICOA Member
ICOA Member
Posts: 178
Joined: Sun Mar 02, 2003 11:07 pm
Location: San Diego, CA
Location: San Diego, CA

Post by Jim-Jim »

I read about a trick someone used on another 'brand/model' motorcycle for squealing brakes. I haven't had occasion to try it but you might give it a go. They said they bought some liquid rubber (spray?) from NAPA and coated the BACKSIDE of the pad plate with a thin layer and this cured the problem. :?: :?:

If you try this, please let us know how it works; brake squeal can be hard to fix but the 'glazing' looks to be the best approach.

Tom Georgi #253

Brake Squeal

Post by Tom Georgi #253 »

Brake Squeal. Yes, well I'm no mechanic but I'll give it a try. Get a brake pad and hold it with the material toward you. Imagine that it is the right outboard pad. What happens as you apply the brakes? The pad moves toward you and the disc, but it also moves slightly to the left in the direction of the disc rotation. Somewhere it comes against something which stops this leftward movement. If it didn't the pads would go shooting out of the calipers. You can get an idea where this point is on page 15-7 of the 79 Honda Shop Manual. In the top picture the arrow on the shim points to this spot on the caliper bracket. This point gets slammed every time you hit the brakes. The harder you hit them the more it wears. Eventually a gouge will develope which is deep. As you look at the pad you are holding this gouge prevents the left side of the pad from moving unless you mash the brakes. The right, leading, side of the pad moves twice as fast, toward the disc, with less force and a fraction of the contact area. This is where the squeal comes from. I don't know if you can get in there because I haven't gotten that deep in mine, but either file, sand ( or glue/weld a piece of metal ) or do something to get rid of that gouge. Then really smooth out the contact area and lightly grease it. Do this for the contact areas of all the pads. Before you put the pads back on look at the metal contact areas of these. The backing metal is just punched out of a big sheet and may have burrs all the way around it. File these smooth and slightly round them so that they don't dig into the caliper bracket and start digging the gouges again. Lets see if that works for you.

E Lee

Brakes

Post by E Lee »

Frank,

Was helping a friend try to solve same problem recently. The Sanding only worked for about 1 mile.

Went through a lot of thought and because I'm lazy took the easy way out. Now this does not sit well with most but desperate people do desperate things.

I "figured" there was something with the new pad that did not agree with the rest of the brake assembly. I figured if it squeeks "OIL" it. Of course we know oil on a brake is a bad thing but.....

Scientifically I put a drop of light machine oil on my finger then placed on the rotor just inside the pad contact area, outside surface only, i.e. towards the axle all the while slowly rotating the wheel. To make a long story short the noise stopped with no loss of braking power. 500 miles later noise came back; same thing and has not occured again.

Conclusion; The only thing I can think of is the new pad was just a little different in how and where it contacted the rotor, because of this it was rubbing on a small part of the rotor that was slightly different - never been touched by a pad (rough/rusty/dirty/ diff. thickness) surface. So oil helped either smooth down this surface of rotor and or kept things quiet while surface was making it's dent in pad.

Good thing is did not have to go through a lot of expensive, time consuming trial and error.

To all, I apologize for this but .........

Later,

Ed Lee

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