Front brake noise

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Something between my front calipers and the rotor rub to the point of making a noise twice every wheel revolution on my 73 850 Interstate. It is very audible at slow (under 5 or 10 mph) and I'm would imagine drowned out after that by the engine noise. The rotor has been surface ground but a couple of spots on the edge didn't cleanup. If anything, I would think that these spots would be low and the last to rub. It doesn't appear that this would cause any serious problem but the noise is annoying.
 
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Do you have a standard caliper and disc setup?
I have the RGM and Grimeca setup.
I find my pads are loose in the caliper and shift radially every turn, making a clicking sound. This is because there are no anti rattle shims on the caliper. Mine is getting better as everthing beds in, but is still annoying.
Make sure the pads are not clipping any rivets of anything and check you dont have alump on your disc that is catching.
 

maylar

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What sort of noise? Clicking, squealing, rubbing? Does it happen with brakes applied, or when not?

One source of noise (if you have the stock Lockheed caliper) is the metal dirt shield that's screwed to the bottom of the caliper. That can squeal or scrape against the rotor. Clicking with brakes NOT applied is the pucks being dragged by the rotor and indicates a rotor that's not true. You might also feel pulsing under hard braking.
 
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If you had the surface ground you might have an issue with the mounting surface, that bolts to the hub not being parralel. You might want to check to see if both are true.
 
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The sound is sort of a squeaky rubbing sound that occurs twice every wheel rev when the brake is not applied. It wasn't there when I first rebuilt the stock calipers and mounted the newly surface ground and drilled stock disc but has developed of late.
 
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The 74 has a stainless steel wiper screwed on to the bottom of the calpier, it was a factory mod to reduce the noise coming from the disc accoding to the NOC Commando notes. As yours is a 73 it maybe you are sufferibng from the noise. Doubt the mod works for long as when pushing my bike around the garage it has a scraping niose every rev of the front wheel .

A running engine is the best cure :mrgreen:
 
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My '73 850 was doing the same thing. I sprayed some WD-40 on both sides of the rotor, let it sit for a minute, then wiped the rotor clean. Solved that garage-floor very low speed howl noise.
 
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I wonder if silicone spray would even be better, but one or the other I will definitely try. Thanks.
 
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It could be the pads settling on the pistons. The traditional cure is a bit of copper grease between the pad and piston.
 

Ron L

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I wonder if silicone spray would even be better, but one or the other I will definitely try. Thanks.

Don't spray any type of lubricant on your braking surface!!!!! I would hesitate to even use WD-40 despite the fact that it is more solvent-like, but still leaves a film which can affect brake friction.

I would suggest the "copper grease" or brake grease available from any parts house and try a scotch brite pad on an air grinder (roto-lok) to scuff the disc
 
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kommando said:
The 74 has a stainless steel wiper screwed on to the bottom of the calpier, it was a factory mod to reduce the noise coming from the disc accoding to the NOC Commando notes. As yours is a 73 it maybe you are sufferibng from the noise. Doubt the mod works for long as when pushing my bike around the garage it has a scraping niose every rev of the front wheel .

:mrgreen:

Is this "noise" described anywhere in Norton literature or writers of the time? It is just hard for me to believe that my rotor is warped since it was surface ground and nothing other than ordinary braking since then.
 

speirmoor

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Reviving this thread to aid my front brake issue.Changed the front pads and bled the master cylinder before the empire rally.Brake has never been better but there is now a terrible screech.It only goes away under hard braking but comes back again immediately. Went to get some grease at Strauss to put between the pad and piston but the parts guy said my disc was the problem and to get another one.The front disc is stock and shows no sign of damage.
Any ideas?
 
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speirmoor said:
Reviving this thread to aid my front brake issue.Changed the front pads and bled the master cylinder before the empire rally.Brake has never been better but there is now a terrible screech.It only goes away under hard braking but comes back again immediately. Went to get some grease at Strauss to put between the pad and piston but the parts guy said my disc was the problem and to get another one.The front disc is stock and shows no sign of damage.
Any ideas?

Get it ground, then you'll know. Cheaper than a new one.

What kind of pads did you use?
 
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Before you grind anything, are they Ferodo Platinum pads?
Maybe change them to something else just to see what happens.
I had the same squeal, the kind that makes school children wince and put fingers in their ears, with the Platinum pads under light brake application on a rotor that I blanchard ground the chromium plating off of until it was dead balls parallel with the mounting surface. I have a suspicion the pads are not my only problem since the original pistons were still fitted and we all know how weather resistant they are after 35 years of no dust boots.
Just saying, try to find an obvious issue before resorting to any grinding. GRINDING CANNOT BE UNDONE without replacement.
The stock caliper doesn't float to take up any warping but since it has opposed pistons they can float without greatly influencing the feel if there is any axial runout as long as both disc swept surfaces are parallel, so warping is not super critical for average use within reason of course. Indicate both sides and mark them with a sharpie as you go along so at least you know the disc condition when mounted. If the squeal sounds like a cheap motel bed late on a Friday night then disregard the above and have it cleaned but that should be noticeable in the hand lever without the bother of indicating.
Brake squeal can be an sob to mitigate and what you really end up doing is moving the resonant frequency to a range that the human ear cannot perceive. But try the easy things first. Make sure both pistons are free to move, grease the backings, then try some of the anti-squeal shims, I made my own from a kit that was big enough to cut up. Use the scientific method, one change at a time, and please report the findings. My shims made no difference at all.
My unit is still up on the table since the new caliper pistons (and many ongoing reliability / maintenance items) so I have nothing to report as yet.
So, what are the pads?
All the best.
 

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Yep thats the wincing squeal. The pads are Emgo ones. The braking has been great with these pads.
I'll try the EBC then if the Ferodos have the same characteristics.
 
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In my personal experience the Ferodo's are running on a disc with the chrome removed, ie cast iron, and a questionable caliper condition.
Your experience may be different on your still as yet chromed disc. I would not rule out any pads on hearsay, you must try them yourself.
But yeah, the friggers could chirp the TT100 tyre with a VERY quick heavy hand but squeal awful when lightly applied. Stock 5/8" MC.
Please keep up abreast.
All the best.
 

speirmoor

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Went with AP Lockheed pads in the end and threw them on this evening. No Joy. All was well for first 5 miles but by mile 10 it was back to the same old screeching. Is it time for the blanchard treatment or is there something else I can try? Kinda really want the disk ground and drilled but was hoping to put it off for a while.
 
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They sell a disc brake pad 'glue' that sorta binds pads to pucks to keep in place for installs and stifle that source of noise. The kind I got was orange red color but pretty standard off the shelf autoparts available.
 

speirmoor

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Tried this and at the moment it "works".Took two attempts as it didnt work the first time.On first application I used bike right away with no luck the second time I let set over a couple of days and noise has dissipated.
Front brake noise
 
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