Author Topic: Brake squealing  (Read 283 times)

Matt2matt2002

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Brake squealing
« on: October 03, 2018, 05:15:16 PM »
A set up a new pair of blue Swiss tops on my Case rims but had a terrible squeal start.
Toed them in. No luck
Swapped front to back
. No luck.
Narrowed the squeal down to one side on the front.
Removed pad and holder and discovered a wobble on the threaded part that enters at right angle to the holder.
The other 3 holders don't have a wobble.

Decided the wobble was the cause and called SJS.
Nice young man suggested part 30195 which although not specifically for XTR, should fit.
Reduced to 11 from 23!
Comes with pads but I should be able to swap them over.

I'll let you know if the squeal disappears.

Anyone else had this problem?
« Last Edit: October 03, 2018, 05:17:09 PM by Matt2matt2002 »
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jags

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Re: Brake squealing
« Reply #1 on: October 03, 2018, 10:48:21 PM »
when i used to ride with the group i loved it when my brakes squealed used to craic up the glory riders ;D ;D ;D
long live squealing brakes.

anto.



John Saxby

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Re: Brake squealing
« Reply #2 on: October 04, 2018, 02:39:37 AM »
Och, but you're a terrible man, Anto  ;)

martinf

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Re: Brake squealing
« Reply #3 on: October 04, 2018, 08:09:54 AM »
Squealing brakes are useful to warn pedestrians on shared paths, IMO works better than a bell.

But the noise annoys my wife when I ride with her, so I generally try and eliminate or at least reduce squeal.

geocycle

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Re: Brake squealing
« Reply #4 on: October 04, 2018, 09:01:57 AM »
I like my brakes to be silent along with the rest of the bike.  However, the squeal ghoul does seem to make random appearances.  I've never had a problem with swisstop blues and CSS rims.  Just this week my front wheel which is now non-CSS grizzly with standard (Aztec???) blocks started practising for Halloween with no warning and having been fine for months.  Then equally suddenly it has stopped, no idea why!
 

Matt2matt2002

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Re: Brake squealing
« Reply #5 on: October 04, 2018, 11:58:05 AM »
Any thoughts on the causes if a squeal?
Grit? Grime?
With me it was/ is definitely one-sided.
Hopefully a new pad holder will solve the issue.
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geocycle

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Re: Brake squealing
« Reply #6 on: October 04, 2018, 01:40:17 PM »
Any thoughts on the causes if a squeal?
Grit? Grime?
With me it was/ is definitely one-sided.
Hopefully a new pad holder will solve the issue.

No clear idea.  the rim looks clean but I guess some grime is involved.  It's certainly possible that alignment including toe-in, unequal horizontal pull and being not parallel to rim as well as being solidly bolted could contribute. Some blocks compounds might also be to blame, especially if they are prone to picking up debris like Shimano ones.
 

Matt2matt2002

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Re: Brake squealing
« Reply #7 on: October 04, 2018, 03:02:51 PM »
I'm guessing that a squeal is caused by air vibration.
If parts ( pad and rim ) are not seated square then the slight movement will result in squeal.
Any squeal experts here?
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John Saxby

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Re: Brake squealing
« Reply #8 on: October 04, 2018, 03:23:07 PM »
Quote
Grit? Grime?
...and Gremlins.

Making a virtue out of necessity, and following Martin's experience, I've found that the occasional rasping squeal does give a very clear warning to pedestrians. (I've never heard anyone say, as I have on occasion with my Raven's bell with its lingering temple-bell chime, "What a nice bell!")

I use Kool-stop salmon, and occasionally dual-compound pads.  Sometimes, they squeal a bit after cleaning and readjustment, but that lasts only for one or two applications, and occurs only on hard braking, e.g. for downhill hairpins.

jags

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Re: Brake squealing
« Reply #9 on: October 04, 2018, 05:12:36 PM »
Och, but you're a terrible man, Anto  ;)

and that's the truth John  ;D ;D

Matt2matt2002

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Re: Brake squealing
« Reply #10 on: October 07, 2018, 03:23:46 PM »
Good news and maybe not so good news.
I placed an order for replacement pad holders.
I had identified the squeal as coming from the front near side brake pad. The holder was not firmly attached to the part that holds the washers and nut. It wobbled. The other 3 holders didn't wobble.
So that must be the cause. Right?

The order arrived within 3 days. As well as the brake shoe set ( Shimano M70R2 ) I ordered a Profile Design bottle holder to match the 2 I already have, 3 spare drain plugs ( I'd dropped one the last time I did an oil change ) , ,3 SKA mudguard draw bolts, Schwalbe inner tube and and oil change kit. All well packaged.

However, upon examination both brake shoe sets wobble in the same way as the ' faulty' one that I think causes the squeal!

I've yet to swap the brake shoe but not optimistic about it curing the problem.

Any thoughts folks?
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mickeg

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Re: Brake squealing
« Reply #11 on: October 07, 2018, 04:31:58 PM »
...
I placed an order for replacement pad holders.
...
The order arrived within 3 days. As well as the brake shoe set ( Shimano M70R2 ) I ordered a Profile Design bottle holder to match the 2 I already have, 3 spare drain plugs ( I'd dropped one the last time I did an oil change ) , ,3 SKA mudguard draw bolts, Schwalbe inner tube and and oil change kit. All well packaged.
...
Any thoughts folks?

I am sure that changing a Rohloff drain screw will solve your brake squeal problems.

Just joking, I could not resist.

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When I did my Pacific Coast tour, I recall telling my touring partner that he should get a bell for his bike - and I told him that a bell would have a much more pleasant sound than the brake squeal that he was using to warn others of his approach.

energyman

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Re: Brake squealing
« Reply #12 on: October 07, 2018, 05:22:27 PM »
............................and nobody has mentioned that universal cure all WD40 !

Matt2matt2002

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Re: Brake squealing
« Reply #13 on: October 14, 2018, 04:17:20 PM »
Further research...

The new brake pad holders wobble in the same manner as the ones I am using so I didn't bother to swap pads to see if that solved the mystery

I swapped front and rear brake shoes and pads.
The squeal was still at the front!
So my conclusion is that it's a rim problem.
I cleaned the CSS rim with white spirit, let it dry, cleaned again with dry tissues, but still the squeal.

My rims came with the bike second hand.
Age of bike from Rohloff hub dating ( I know it's not accurate but.....)
is 10 years.

Any thoughts on how to proceed?
The novelty of waking up half the street when I return home from a late shift had worn off.
« Last Edit: October 14, 2018, 04:19:46 PM by Matt2matt2002 »
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mickeg

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Re: Brake squealing
« Reply #14 on: October 14, 2018, 07:29:39 PM »
Vary the amount of toe in, either less or more.

Some bikes I have had with brake squeal, often it has eventually gotten quieter, so each time you try something, ride for several days or a week before trying something else.

If that does not work, try cleaning the wheel with soap and water.  And take the wheel out so you can clean the pads with soap and water with a brush.  I am in USA, a soap that is particularly good at cleaning off petroleum residue is Dawn dish soap, I do not know if that is sold where you are or not.

If the above does not work, try lightly sanding down the surface of the pads.  But those pads are expensive, do not wear too much off of them.  If there is any coating of something on the pads that is contaminating the pad surface, this could reduce that contamination or eliminate it.  I only mention this because on some of my non-CSS bikes, when I have a lot of Aluminum Oxide built up on my pads, I often sand most of that Aluminum oxide off of them to get back down to the rubber.  Thus I regularly sand down rim brake pads.

If nothing else seems to work, squeal is a high frequency oscillation, can you figure out exactly what is vibrating?  If you reach down to the brake area while riding, be very careful you do not get your fingers caught in anything.