noisy front disc brake after pad replacement

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gerrymcm
Posts: 450
Joined: 30 Oct 2012, 2:52pm

noisy front disc brake after pad replacement

Postby gerrymcm » 17 Oct 2014, 9:56am

I've recently replaced the pads on my hydraulic disc brakes and bled them at the same time. I replaced the Shimano standard ones with a cheaper make, discobrakes I think but I stuck with the same type, i.e metal sintered. Now when the front pads are wet I get the most annoying squeal/shudder/reasonance from the front fork. As it dries it decreases and goes away but id like to eliminate it completely and go back to nice quiet braking.

I took the brakes completely off and cleaned them as they had many years of crud and inspected the mounts and brake adapters etc so it's possible that something has not gone back perfectly but I've had the brakes off a few times over the years without problem.

Please could people offer some pointers.

Thanks

Gerry

DevonDamo
Posts: 544
Joined: 24 May 2011, 1:42am

Re: noisy front disc brake after pad replacement

Postby DevonDamo » 17 Oct 2014, 10:49am

Changing brake pads alone can cause squealing in the wet. I get my pads from Superstar Components. Their sintered metal pads are always silent, and are excellent value for money. However, last time I ordered some, they were out of stock, so upgraded me to their kevlar ones for free. These squeal when wet.

It could be that you have other problems following the rebuild. However, I'd first check with some known 'non-squeal' pads. (Nobody will be able to diagnose a fiddly little problem with your brake reassembly through what you write on here.)

gerrymcm
Posts: 450
Joined: 30 Oct 2012, 2:52pm

Re: noisy front disc brake after pad replacement

Postby gerrymcm » 17 Oct 2014, 1:54pm

Sounds sensible. I kept the old pads and the back pair were not that worn so maybe I'll go back to them for a test.
I reckon I'll strip and set it all up again just in case and maybe splash on the Shimano originals.

Thanks
Gerry

Milfred Cubicle
Posts: 311
Joined: 29 Aug 2007, 8:55am
Location: Co. Durham

Re: noisy front disc brake after pad replacement

Postby Milfred Cubicle » 17 Oct 2014, 7:57pm

I don't want to insult your intelligence, but did you 'glaze' the pads before use?

gerrymcm
Posts: 450
Joined: 30 Oct 2012, 2:52pm

Re: noisy front disc brake after pad replacement

Postby gerrymcm » 17 Oct 2014, 11:54pm

Milfred
I'm not insulted and thanks for chipping in.

When you say "glaze" them before use, does that mean give them a rub with sandpaper or abrasive surface?
If yes then I didn't do this as I assumed that being new they wouldn't need it. I thought this happened after you "dragged" your brakes.

What I've read from a few places on the web is that once fitted new pads should be vigorously applied multiple times to "bed them in" i.e. make the pads mate to the circular groves on the rotor.

I thin I've got a few things to go on but any more suggestions would be welcome.

Thanks
Gerry

andrewjoseph
Posts: 1420
Joined: 17 Nov 2009, 10:48am
Location: near Afan

Re: noisy front disc brake after pad replacement

Postby andrewjoseph » 18 Oct 2014, 9:44am

I use superstar and disco pads on my mtb and road bike, trying the Kevlar pads after using sintered for years.

I find them quieter but occasionally do squeal a bit.

If it's really bad, put some gritty mud on rotor and do some hard stops. Clean and check for noise.

I use meths to clean rotors and pads.
--
Burls Ti Tourer for tarmac
Saracen aluminium full suss for trails.

Brucey
Posts: 42931
Joined: 4 Jan 2012, 6:25pm

Re: noisy front disc brake after pad replacement

Postby Brucey » 18 Oct 2014, 10:15am

on most disc systems it is a good idea to put a little anti-seize on the back of the pads. This can help quell the vibrations that cause squealing.

On car and motorcycle brakes 'anti-squeal shims' between the pistons and the pads are commonplace but I've not seen similar items on bicycle brakes.

cheers
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