Yet another brake squeal question.

[Andy_G]

I'm totally baffled as why my brakes are squealing.
I've used brake cleaner to clean my discs and I've replaced the resin pads front and back but it's still there.
When I put the calipers back on I squeezed the levers so they would fit square before tightening them I've tightened every thing holding it on.
I know on cars you put copper grease on the back of pads but I was told not to on MTBs.
Any other ideas.

 

[ianrauk]

I put Copper grease om the rear of my pads. It does help with the noise,

 

[Dragonwight]

Disc warped maybe?

 

[Andy_G]

I sanded the discs and it still happens.
The discs seem straight and copper grease is next and its the only thing left to do.

 

[Globalti]

Try grinding a chamfer on the "leading" edge of the friction material on the pads.

 

[Banjo]

Try scrubbing the discs with soapy water. I know you said you used brake cleaner but its still worth a go.It worked for me once.I think the brake cleaner is too harsh.