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Answered Help needed - rear brake squealing like a Foghorn and vibrating.

R120

R120

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So after about 20 miles into my maiden outing on my new E-Sentier hardtail this morning, and having though i had beded in the brakes on a quick ride last night, the rear brake started squealing badly, like a foghorn, and sending a lot of vibration through the bike. No idea why, and never had this problem before. Bike is an E-Sentier Hardtail, with Guide RE's. Any help appreciated as at this point i am thinking of just getting a new rotor.

IMG_1992.jpg
 
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Squealing is usually vibration at hyper high frequency.
Are you aware of any contaminate (like oil) getting on the pads or disk? If so that’s mostly likely your answer, cleaning the pads and rotor can be a bitch, but isopropyl alcohol is a decent start.

If not, there are loads of potential reasons but a good place to start is to remove the pads and put a light smear of coppercrest/coppaslip grease on the REAR of the pads, then reassemble. Be careful not to contaminate the front of the pad or the rotor.
 
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Thanks both - my first though was contamination, but i haven't put anything on the bike, and pretty sure didn't ride though anything, so unless CRC contaminated the discs i am at a loos at to how they could get contaminated.

I will try cleaning them with some isopropyl wipes i have, and re aligning them. Super frustrating as it has pretty much made the bike unridable
 
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R120 said:
Thanks both - my first though was contamination, but i haven't put anything on the bike, and pretty sure didn't ride though anything, so unless CRC contaminated the discs i am at a loos at to how they could get contaminated.

I will try cleaning them with some isopropyl wipes i have, and re aligning them. Super frustrating as it has pretty much made the bike unridable
Click to expand...

Definitely give the coppercrest a try in that case, it’s surpsirisng how much sqeal it can solve. I tiny tube isn’t expensive and will last a good while.
 
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So i took off the disc and pads, sanded them down, cleaned them, re centered everthing, and after about 4 gentle stops it returned! Hmm
 
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No didn’t use any grease, will get some tomorrow.

The vibration is so bad that I have a feeling something is up with the rotor, the whole bike vibrates badly.
 
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I’ve had this a couple of times now when no amount of adjusting cleaning has sorted it , new pads and light sanding of the rotor was the cure .
 
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Every type of sram brakes I have owned had the sticky piston disease.
1 of pistons don’t retract after breaking resulting in brake pads in a bad position and rubbing against the rotor with a edge of the pad.
If this edge is in the counter direction of the movement of the rotor I got the vibrating.
Is easy to check if you take out the pads and check your pistons movement if you apply gentle movement in your brake handle.
 
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Yup, had considered that by worried if something up with the pads on the sentier could contaminate the disc from the sommett
 
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A disc can’t get contaminated like pads. , metal cant absorb oil. Just clean it and rub over with some fine abrasive incase it’s glazed .
If you can get the brake really hot by braking a lot then pour water over it , works but it’s got to be hot
 
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Be careful because you absolutely CAN contaminate a disk and it can be a complete bitch to recover. It can need skimming on a lathe or only fit for the bin.
 
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Unfortunately this isn’t just a squeal, it’s like someone stuck a jackhammer in the rear axle
 
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R120 said:
No didn’t use any grease, will get some tomorrow.

The vibration is so bad that I have a feeling something is up with the rotor, the whole bike vibrates badly.
Click to expand...

Forget the grease as the fixer in this case, if the whole bike vibrates it’s a tolerance issue somewhere. Can you get it back to the shop as it’s so new?
 
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Nope

Think I am just going to take everything off and build it back up
 
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So a long day today

Went to Evans first thing to get some new pads, and a new rotor.

They didn't have a Sram rotor but did have a Hope Floating one, which the assured me would work with the Guide RE's - looked the nuts so i thought why not.

Get back home, and lo and behold they have given me the wrong pads, but i did mount the rotor, but couldn't put the wheel back on till i got the right pads.

Back to Evans to return the wrong pads and get the right ones (turns out their computer has the wrong info listed).

Back home, do the pads, mount the wheel with Hope rotor, and lo and behold its rubbing - specifically the bolts/rivets connecting the inner and outer parts of the disc, hitting the calliper body as they are just a tad to close to the outer of the disc and run the bottom of the caliper.

Much swearing ensures. Get the Sram rotor out the bin, and decide to sand the hell out of it again, clean it all up, and put it back on. Doubly gutted by then as was loving the look of the hope, only to be denied!

Finally all back together, took the calliper off, put it back on, checked the wheel and nothing loose etc etc.

Now trying to decide if i want to take it out in the pouring rain to see if the issue still persists.

IMG_1994.jpg
 
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R120 said:
So a long day today

Went to Evans first thing to get some new pads, and a new rotor.

They didn't have a Sram rotor but did have a Hope Floating one, which the assured me would work with the Guide RE's - looked the nuts so i thought why not.

Get back home, and lo and behold they have given me the wrong pads, but i did mount the rotor, but couldn't put the wheel back on till i got the right pads.

Back to Evans to return the wrong pads and get the right ones (turns out their computer has the wrong info listed).

Back home, do the pads, mount the wheel with Hope rotor, and lo and behold its rubbing - specifically the bolts/rivets connecting the inner and outer parts of the disc, hitting the calliper body as they are just a tad to close to the outer of the disc and run the bottom of the caliper.

Much swearing ensures. Get the Sram rotor out the bin, and decide to sand the hell out of it again, clean it all up, and put it back on. Doubly gutted by then as was loving the look of the hope, only to be denied!

Finally all back together, took the calliper off, put it back on, checked the wheel and nothing loose etc etc.

Now trying to decide if i want to take it out in the pouring rain to see if the issue still persists.

View attachment 3544
Click to expand...

Bloody hell what a day, and Evans continue to shine then.....

Hope you sort it soon.
 
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I didn't even mention i had to fit a trip to Ikea in croydon in-between bike bodging!
 
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Hope parts have always been this way
, you really need a hope hub, hope caliper and hope rotor from the same range to guarantee fit.
I always make sure that on new pads I don't drag the brakes but stop hard to get the new material onto the disc seems to work
 
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