As i know there are a few mechanical minds on this forum, u may be able to help......

been struggling for a few weeks with brake vibrations though the steering wheel. Below 60 mph nothing really shakes......when the pads/disks warm up and you brake down hard from higher speeds there is some serious wheel shaking going on!! Which then continues at lower speeds braking down to a stop.

had the wheels balanced and alignment done.......no improvement.

stripped the brakes down at the weekend, to check everything is sliding smoothly, greased the slide pins and the mounting points caliper to anchor plates were all smooth........now the strange part!!!!

The outside face of the disk, is smooth and nicely greyed/shiny.........on inspection the inside face was heavily mottled and shpwed signs of patching!!!! Must be the cause!!

Now what i do not understand is how this can happen.......the twin pistons are on this face and must force ahainst this side of the disk to pull the calliper in to the outside face......outside of disk on both side of car is fine. Inside faces are not good both sides....

anyone any idea or experience as to how this can happen???

Thanks guys.

 

I've been following this forum for a little while and I thought I'd register to give you a reply, Damienedwards.

It sounds like you have the exact same thing I have, wheel shake, mostly from high(ish) speed, worse when the brakes are warm. I have OEM discs and I HAD red stuff pads. I've since changed the pads as after only 10 months, the inside pads are completely shot (down to 1mm), however, the outside pads are ok. I went on one half-day track event. Otherwise I'm pretty light on the brakes.

Changing the pads hasn't really helped. I'm going to have to change the discs as well. I've been chatting to Spires here in the UK and they really don't rate Red Stuff for the XRF.

Here is a picture of my front pads (thin pads are the inside pads, thick pads outside)

 

Very common occurrence on many car types. The mottling is deposits of pad material, the binder/glue stuff that holds the friction material together. It can easily be removed with a coarse sanding disk. 3M makes a kit.

Do NOT let your garage talk you into machining the rotors. Walk away if they insist they are warped.

 

Curse of the RED stuff pads!!!

Just don't understand how the calliper seems to work fine on the outside face and not the inside.......where the pistons are!!!!

 

Less cooling air? Dunno. It's not rare. My SUV has it right now, outboard rotor surfaces are perfect. Inside are cr*p.

 

Pic of the inside of one of the disks

 

I had aftermarket brembos on my old turbo focus, and oem brembos on my 350z, both cars had similar issues. doing a "break in" procedure usually fixed the issue, and if it didn't I would have to scuff the surface as mentioned previously in this thread.

Pad deposits on the rotor are very common and it is what usually perpetuates the "warped" rotor myth.

 

Agree with all of the above. Try rebedding the pads. If that doesn't work, an abrasive will be necessary. Mikey mentioned one method in his post above. Some guys at the track swear by Scotchbrite and Brake Kleen; can't say I have ever tried it myself. A more expensive method (but cheaper than rotors) is a temporary change to a more abrasive pad.

Once fixed, prevention is the key. You probably know all this already, but: Bed your pads and discs properly when new (I also rebed mine a few times each year). Don't sit with your foot on the brake pedal at the lights, or put your parking brake on if the brakes are hot. Don't wash your car and then let it sit so that the rotors get covered in rust.

 

Check the caliper slides. If they are frozen, they do not allow the outer pad to apply adequate pressure.

 

I thought calliper slides, but then thought it makes no sense as the outside of the disk is fine so the calliper has to be sliding OK......the inner brake pads have to react against the inner surface to slide the calliper and pull the outer in......but it looks like the inners are barely being touched.

I do have a new theory......looking at the service history the brake fluid has never been changed in 60k miles......wonder if the old possibly sludged up thicker fluid is stopping the pistons fully retracting and being held on the inner face at stops......hence the spotting.

Changing the fluid over the weekend so see if this helps