5 replies to this topic

[Sputnik]

Hi,

I have a set of 7.5" cross drilled discs and carbon metallic brake pads. The discs are wearing unevenly, meaning where the holes are drilled in the discs, it seems that it 'eats' a groove in the pads, and then the section of the discs that is not inline with the holes of the discs wears faster, making the wear unevenly. The hole are has therefore less wear. The discs are not warp, they just have grooves running in perfect circles, at the holes they are raised and in the no hole area they form a valley.

The question now is if it is normal and to rectify, can I just skim the discs and flatten the pads to the best of my ability.

The brake setup only done one season of racing and ther is a lot of use on the discs and pads left. The driver side is also much worse than the passenger side.

[Artful Dodger]

Check caliper condition. Could be a caliper piston starting to seize up.

[Sputnik]

Hi artful,

I had the Calipers rebuild by ferodo 10 months ago, but will the cause the uneven discs ??

[MRA]

The question now is if it is normal and to rectify, can I just skim the discs and flatten the pads to the best of my ability.

The question is...what is your ability, I was recently asked to give an engineers report on the state of a pair of discs on an Audi, the owner had fitted larger discs some time in the past, the present owner had used an angle grinder to "flatten" the grooves in the front discs, this lead to his death and very nearly a couple of other drivers.....

I wouldn't bother skimming old discs, simply is not worth it and I own the correct type of equipment.

The reduced mass of your discs will cause brake fade sooner, also if your discs are solid then get grooved NOT drilled as they are just for looks.

Do NOT try to flatten your pads, the dust created even if you have the correct machine will potentially be very harmful to your health,

[Artful Dodger]

racing discs and pads will wear differently to normal solid discs and normal pads. the holes in the discs will eat at the pads , because you have a sharp edge running over the pads. As said, grooved discs are better. more surface area for cooling, creates a fan effect for cooling and the pads will wear evenly due to the groove covering the whole pad, meaning there is no localised extra wear that would be created from drilled discs.

but there is going to be different wear characteristics from racing brakes to brakes used on a road car.

[Dan]

Neither grooves nor drillings in discs are there to provide cooling.