I've had new disks fitted a few weeks ago and the pad were replaced a month or so before that. But since the disks have been fitted they squeek every time I brake. I thought it would fade over time but it hasn't. Is there anything I can do to stop it? 

Take it back to where fitted them or put copper grease on the pack of the pads where the calipers touch the pads.

put a chamfer on the pads leading edge approx. 35-45 deg and 1/16-1/8" wide  and some copperslip    not too mutch

Squeal is usually caused by a dry vibration.

 

There are some good suggestions above.

 

The Octavia pads I've seen already have a reasonable chamfer so that probably won't help.

 

If the pads have been on for a month then you've probably worn off the transfer material.  Unfortunately you don't say what brand/model they are.  If they are cheap, rubbish pads you won't fix permanently them no matter what you do.  Assuming they are "good" pads, you need to decontaminate the friction surface.  Keeping the friction surface parallel with the backing plate, use a course bar steward (stupid censor program) file or course emery paper & remove about 0.5mm of material (you should see the colour change).

 

If they are crap pads the clearances between the pad & the caliper carrier might be wrong.  This can cause squeaking.  Not much you can do except bin them.

 

Clean the inner & outer faces of the rotor with brake cleaner.  Rough them up with emery paper.  Clean them again.

 

You haven't said how old / how many miles.  Seriously consider replacing the slider rubbers & pins.  They are only cheap.  When they get old they cause the caliper to apply unequal pressure and the backing plate doesn't sit flat against the caliper - this can cause squeal.  Make sure the pins are lubricated with a smear of kopr-kote or rubber grease and that the caliper freely moves on the slider.

 

Make sure the caliper carrier rails are wire brushed clean and haven't any chunks out of them due to corrosion.  The bit where the pad touches should be bare metal and the pads shouldn't rattle about.  Apply Kopr-Kote to the machined part of the rail and the part of the pad that touches the rail. - the thinest of smears.  It should be oozing out or be in clumps

 

Make sure the face of the piston and the "walrus tusks" of the outside part of the caliper are free of dirt, corrosion & grease.  These are the parts that touch the backing plate of the pads. Apply a small smear of Kopr-Kote to these parts & also a smear onto the equivalent mating parts of the backing plate.  If it squeezes out past the walrus tusk then clean it off because it will just attract dirt.

 

When attaching the carrier to the hub & doing up the slider pins, try & use a torque wrench (if available) or at least be aware of the correct torque & try & get it near the spec / even.

 

Once it's all together, bed in the brakes as many of them work on material transfer to bed-in.

 

http://www.dba.com.au/tech-article-t017-basic-initial-brake-bed-in-street/

 

http://qfm.com.au/userfiles/files/BEDDING-IN-PROCEDURE.pdf

 

http://www.zeckhausen.com/bedding_in_brakes.htm

Edited 21 July, 201510 yr by brad1.8T