Squealing brakes

[rumpelstiltskin]

Just rebuilt my Brembo calipers,new discs and Mintex pads.Brakes are squealing like a pig,can't understand it as pads have a thin padded backing,plus i had copper grease on them!!Anyway,heard about a product Mintex do called Ceratec,applied this to the rear of the pads,still squealing!!I made sure pads were roughened slightly before fitment,new discs were thoroughly degreased/cleaned,runners on top and bottom of pads were removed,cleaned underneath,straightened out then greased etc etc,can't understand this?
It's not just squealing i'm getting either,if i drive in a straight line then just slightly turn to the left i get a grating sound,very similar to a knackered brake disc dust guard when it scrapes off the disc,but there isn't one!Bearings are both fine and there was no issues with the brakes at all before 'treating' car to discs/pads all round.I've been told to try other pads?Anyone had one make squeak and another not?Cheers.

[226bhp]

Have you tried chamfering the leading edge of the pad? All the various pastes\ lubes are only temp, they soon stop working due to various reasons. People have been battling squealing brakes (especially on Brembos) for years and i've never heard of a permanent solution, you've just got to live with it.

Edited by 226bhp on Sunday 15th June 15:04

[rich83]

Which mintex pads? M1144? M1155?

My M1144 squeal too at low speed if that's any consolation.

[rumpelstiltskin]

Pads are mdb1877on a Fiat Coupe 20v turbo.Top and bottom of pads are chamfered as is,but never thought of chamfering leading edge.I'll try thta,if it fails i'll just ditch the pads and put in a cheap set.Brakes didn't squael once with old discs and pads over the 110 mile journey home when i bought the car!

Edited by rumpelstiltskin on Sunday 15th June 14:30

[The Wookie]

Copper grease, as said, will only work very briefly if at all. You can get more specialised NVH greases (the Mintex one is probably a rebrand of something else), but simple application only tends to work on pad abutment pins/surfaces if that's the problem area. Application to the pistons wont last long unless you have proper grease retaining sandwich shims.

Chamfering might work by changing the centre of pressure if you're lucky but generally only works on squeal that occurs when coming to a halt.

Next stop without changing anything would be to cut the backing shim in such a way that only half of each piston comes into contact with the shim as this changes the centre of pressure.

Another possibility is seal material if you've rebuilt the calipers, if it's slightly different to before (or you didn't soak them in brake fluid before fitting) then it can have an effect on how the disc and pad are conditioned and possibly how vibration is transmitted through the system.

Most likely it's just the pad material, the resonant properties of the disc, or a combination of the two. As it's all new give it a chance to bed properly though (and perhaps a good thrashing), if it was from new and hasn't appeared with time it might well disappear by itself!

[gareyt]

I put new pads and discs on my car a few weeks ago. I brushed off the rust, used brake cleaner, used copper grease on the back of the pads and put it all back together. But it still squeaked.

So I took it all apart and did the same again but this time I applied a little copper grease to the edges of the pads (not on the brake material) Put it all together and No squeaking since

The only other difference was that on the first occasion the weather was damp but on the second occasion the weather was hot.

Don't know if that will make any difference but thought it could help