Disc brake squeal

[silk186]

I seem to have bad luck with disc brakes concerning squeal. The last bike I had, a GT avalanche 3.0 suffered from this as does my current Garry Fischer marlin 2009. The squeal occurs from both the front and back regardless of if they are wet or dry. Interestingly it does not occur when slowing down. It squeals loudly when braking at a slow speed, as in when I've slowed down and am coming to a full stop. The bike has Magura Julie hydraulic brakes.

I just took the bike in to my LBS, the brakes were bled and spacers were added as these brakes lack adjustment.

I've done a bit of reading on disc brake squeal and know I have a few choices.

1. replace my brakes. I don't really like the feel of these brakes and have found some disc brakes on ebay like the Shimano Deore M615 with rotors for £85 which I'm told would be an upgrade.
2. Replace brake pads, I'm told this would require me to re-bleed the brakes (I would need to buy a bleed kit)
3. Buy some disc brake degreaser and try to clean the rotors.
4. Use some sand paper to rough up the rotors and possible sand the break pads.

I'm looking for specific advice and I don't want to spend more money than necessary.
ex. If I buy brake pads, what pads are best to buy (I ride to work rain or shine)?

 

[Globalti]

A loud juddering squawk from disc brakes just as you roll to a stop means the discs and pads are contaminated with something oily.

Put the pads in the dishwasher - nothing is hotter or more caustic, and clean the discs with very hot water and detergent or alcohol or glass cleaner.

 

[Drago]

^+1

And degrease the discs, and scuff up the glaze on the pad surface. Most pads need to go through several controlled heat cycles to bed in properly. Read up on bedding in new pads.

 

[silk186]

Great, I will try both of your suggestions.