GoodfellaFD3S

iTrader: (213)

I'm putting new EBC reds on my fronts within the next few days. I have a pair of the stock sized Brembo slotted cross-drilled rotors on the front, the kind that are sold on ebay.

Can the rotors be cut? Is there some kind of special procedure? Any insight would be greatly appreciated

djantlive

This exact topic was discussed 10 months ago or so.

Someone claimed to have done it.

I did some lathe myself on non-automotive work. Although it may be done, it's very hard to do it right and leave a nice smooth surface.

Tim McCreary

I'm no expert in this area, but have some machine shop knowledge. You would need to surface grind the rotor instead of "cut" with standard brake lathe equipment. The cutting would be severely affected by the holes and grooves. The tip would bite in everytime the lathe hit the rotor. After surfacing, the holes would need countersunk again for stress relief. Also, by taking off part of the surface, the grooves would be less effective than before.

Tim

Vintage Red Touring

I have slotted and cross drilled Brembos on all 4 wheels, so I'd like to know what to do when I have to have them resurfaced as well.

DamonB

I don't know for certain, but I bet 99% of the places can't do it. Tim is right; you couldn't use a regular cutter which all the shops use as it would gouge the cross cuts. I think they would have to be done with some sort of rotary cutter or grinder and then you are talking MACHINE SHOP which would probably not make economic sense.

GoodfellaFD3S

iTrader: (213)

This a reply from a big list member:

<<Rich,
Your pad choice seems to say they're for street use rather than track. The
red is a soft pad, totally unsuited to serious road course stuff- it will
fry quickly- but it is a good street pad. I use Porterfield R4S on my
street cars and I'd say the same thing about them. (My 3rd gen is "track
only" ands uses PF93 pads up front- I am an instructor for many track groups
at places from Sebring to the Glen but most often at VIR)
As such, it will also bed quickly on any rotor.
One should never bother to grind a warped rotor it will only rewarp- replace
if that is the case.
Also replace when you wear to slot depth- for most rotors they are cut very
similar to the rotor wear limit.
You do not need to do anything else
Regards
Paul Winter>>

seems like I should be ok just leaving the rotors as is. I guess I'll find out

rswst8

sounds like you're only concerned about bedding in the new pads to the old rotors. don't worry, it's actually better to bed the pads on used rotors unless they are heavily worn or scored. just follow bed-in directions from EBC. if anything, maybe just hit the rotors with a wire brush.
the slots in the rotor are there to help prevent pad fade, anyway

maxpesce

If the rotors are not heavly scorred or worn down past their wear limit (21mm for stock rotors) just hit them with some 80-100grit sandpaer on a orbital sander. Sand them just enough to pull the GLAZE off the rotors and provide a matt finish surface to seat the pads into.

duboisr

Garfinkle cross drilled mine several years ago , they were turned at the local auto parts store a month ago .All is smooth and quiet ,no problem