Wacky Brake Wear

[Reedy]

I pulled my track pads + rotors off yesterday to fit my street set and noticed some rather uneven wear on my pads. These are Project Mu Club Racer pads that have done 4 track days on my MPS.

https://dl.dropbox.com/u/3223840/Pho...s/IMG_1304.JPG
https://dl.dropbox.com/u/3223840/Pho...s/IMG_1307.JPG

The left and right pads are wearing in opposing ways and in such a way that the calipers are buckling inwards at the top under the braking forces (think negative camber).

Now this is obviously thanks to the sliding calipers that this car has moving around under the braking forces but I want to know if an effect this pronounced is likely to cause me any problems, I certainly haven't noticed anything while driving but it only takes a simple geometry lesson to realize that this is leading to slightly less than optimal braking force being applied to the pads along with the uneven wear reducing the life of them.

I could swap left & right around and have them wear back the other way but that kinda stuffs the idea of having discs and rotors matched and properly bedded in when I put them on.

Is this an actual problem or typical of this kind of brake setup?

[Glenno]

The only noticable problem you will get is descreased pad life due not being able to use all of the material.

You need to flip the pads between sessions if you want to manage taper wear. If you flipped them now you would have massive issues with braking.

If you wanted to flip them now you could linish or mill them back to flat, rubbing them on concrete in figure 8's also works.

[Reedy]

Ok so the short story is that it's not necessarily a problem, and to rotate my pads/rotors in the future.

I'm not surprised to be seeing this considering how much play there is in the floating calipers on my car. Altho with these Pmu pads and semi slick tyres the temps and forces being applied are quite a lot higher than the stock setup will ever see so the effect has been amplified.

[Momus]

Typical problem and not particularly severe looking at the pads.

Having a thick pad back plate- yours look ok- seems to help these issues- the pad dousn't flex and the caliper behaves a bit better.

[Reedy]

Here's a video that shows how the caliper behaves when I put the wonkily worn pads in and pump the brake pedal, the movement is in the guide pins, I had it backwards as well, they are swinging in at the bottom of the caliper, not the top. The braking forces are just pulling on the caliper in that direction and the play in it is making the pads wear unevenly.

http://www.youtube.com/watch?v=MNwcKR5Duww

[dattoman1000]

Most production calipers are shite
Yours are no exception
Thats mostly normal... but not very nice all the same

[spiller]

If you wanted to flip them now you could linish or mill them back to flat, rubbing them on concrete in figure 8's also works.

Is this an acceptable method if you want to reduce the thickness of your pads slightly? I have a brake set up that uses a slightly thicker rotor than what the caliper is designed for so its an absolute cunt to fit new pads and they probably drag on the rotor when new. Would rather do it myself on concrete than fuck around paying a brake shop to machine them to the right size.

[Reedy]

Well i've ordered a new set of pads, GSL had a 20% off sale so I jumped on a set of fronts. I will rotate these ones side to side and see how things go this time around. That amount of uneven wear was created after only 4 track days so I hope to get a bit more life out of these ones. At $350 just for a set of fronts I don't want to make a habit out replacing them that often.

[Reedy]

Just took the new pads to the track for the first time and after 1 track day the uneven wear is starting to become apparent already. Nothing drastic but as long as I rotate them every second track day I reckon it'll be fine.

[Glenno]

Is this an acceptable method if you want to reduce the thickness of your pads slightly? I have a brake set up that uses a slightly thicker rotor than what the caliper is designed for so its an absolute cunt to fit new pads and they probably drag on the rotor when new. Would rather do it myself on concrete than fuck around paying a brake shop to machine them to the right size.

Spiller yeah I have had the same issue, concrete FTW

Just took the new pads to the track for the first time and after 1 track day the uneven wear is starting to become apparent already. Nothing drastic but as long as I rotate them every second track day I reckon it'll be fine.

Roatate them every track day or you will end up having to much taper to wear back flat.

[dynoryder]

Coarse sandpaper on a flat bench is better then concrete because it is flat and there is not to many slabs with a rough finish that are completely flat.

[Reedy]

Roatate them every track day or you will end up having to much taper to wear back flat.

By that I mean rotate them now and then every second one, next track day wears them back to flat, one after that technically it doesn't matter which way they are in, then rotate again once they start wearing in the other direction. If y'know what i'm sayin'.

[Momus]

Fix the farkin caliper issue... concrete is expensive...