Ridges in front brake discs

[Erolc]

Hello all.

After some heavy breaking on news pads and discs all round, I overheated the brakes and the discs on the front have formed ridges, (sharp little bumps accross each whole disc). The braking effect after this is significantly reduced. So, I have bought new pads which hopefully I will fit tomorrow. However, I'm presuming that the pads have worn to fit these ridges and are therefore "ridged" in the opposite pattern. Therefore, when I put the new discs on the pads will have gaps in the contact area.

My question is, will the pads wear down to a smooth normal surface and be fine with the new discs or will the breaking be rubbish unless I get new pads as well? I presume the ridged pads wont be harmfull to the new smooth discs?

Thanks for all your help in advance :)

Erolc1993 520i

[Erolc]

I've just got it to the point where the caliper is off the disc, I have taken the worn pads out and the new ones are too thick to go in!!!! What order do you put the pads back in? Is there a special method because the olds ones just pulled straight out easy.

Erolc1993 520i

[dusty21]

Press the caliper piston back in until it is flush.

I use a screwdriver to pry between the rotor and inside pad
before removing the caliper and old pads.

If you already have the caliper off, then use a "C-Clamp"
or special tool to push the piston in until it is flush.

Then the new pads will fit over the rotor.

[Bonzo]

It sounds like your ROTERS have groovs which are causing the ridges in your brake pads, you need to fix the problem and not the symptom.
Have your roters turned (resurfaced) or your breaking ability will deminish by one third even with new pads, not to mention the money spent on those new pads.

[Erolc]

Thanks mate, you're right. I had a look at the pads and discs and in the end it was worth getting both new so I have done. Bit of money but worth it for brakes. They will be much nicer.

Erolc1993 520i

[Erolc]

Cheers Dusty. I did use a G-clamp to push the piston in until it was flush. But, the caliper is split into two parts, the main bit and the bit that slides off (excuse me I don't know the names). If I took the bit that slides off and put the two new pads in they fit perfectly over the disc (with the piston sitting flush). However, with the pads in you can't put the sliding part back onto the caliper. It has to be on before the pads are put in and I couldn't fit them in still somehow, I'm sure I'm just missing something simple. The two bits of metal that stick out from each pad seemed to get in the way. I'm still a bit confused!

Erolc1993 520i

[dusty21]

With both halfs of the calipers assembled, place the
brake pads into place using the slots in the caliper that carry the
tabs of the pads.

It will be a snug fit, but you can then insert the caliper
over the rotor in between the pads (with a little rocking back and forth).

Then fasten the bolts to the caliper

[Erolc]

I was wondering if you had to leave the two calliper parts assembled, good. I think I was just being a bit slow at the time then, I'll have another look. And tabs! I couldn't find the name of those, good to know cheers.

Erolc1993 520i

[Gruss]

The only part of the caliper you remove to change brake pads is the part that is mounted with the 2 allen bolts. You probably need to remove some brake fluid from your master cylinder resevouir since you had to push the caliper pistons in so far. You can use a turkey baster or a large syringe. Remember brake fluid is an excellent paint remover!