Is it possible to machine down cross-drilled rotors?



Modified by Cee_mon at 4:33 PM 11/17/2003

 

From my understanding, you can not / should not turn any crossdrilled or slotted rotors. They are the one time use bling rotor.

 

no its not..it will crack

 

Im not saying that im right. So dont flip when I say this.

I have turned a set of crossdrilled and slotted rotors with no problems.
I was simply told that once you get to the bottom of the chamfering of the holes its time to toss the rotors for new ones.
Heres a pic of them and they are still stopping strong btw.

EDIT: Sorry I forgot to mention when I turned the rotors I removed very little material. Enough to take off the rust from being stored for so long from the previous owner and there was a couple small lines. I dont have the time too look right now but I bet brembo has this question in there FAQ section.


Modified by func-tion at 12:47 PM 11/17/2003

 

you can do it but you are not supposed to

 

From what I hear it's not recommended because they'll be prone to warping easier. If any rotor is warped(shaking steering wheel when breaking) then you might aswell get news rotors cuz if you machine them they just that much weaker. In other words if the pads are just worn, replace the pads. I've done this with my Brembo rotors and everyting is fine and I had them for well over 5 years. My experience with machining others rotors have warped over a matter of time.

 

well i have a local shop that will turn them.....but with no promises on results.
Should i put on the rotors in used condition or resurface...they will only be used for maximum of 6 months.

 

Just make sure they dont go below the chamfering. And take it easy on them for the first day so you know that they are sound.

 

They cannot be turned the "traditional" way.....take them to a flywheel and clutch shop they can turn them there no problem......its okay to t urn a slottted/drilled rotor, but like regular rotors the rotor can only be turned so muc hbefore its worn out....I've turned my rotors 2 times in the 3 years I've had my car....and no problems...

 

Well the shop that said can do is an idustrial supply store. They have never done any cross drilled before but they said they would try....So is there any info that i should tell them if i choose to do my rotors?

 

I would say that it does depend on the rotor...

 

rotor is brembo cross-drilled.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SloCivicHMM &raquo;</TD></TR><TR><TD CLASS="quote">They cannot be turned the "traditional" way.....take them to a flywheel and clutch shop they can turn them there no problem......its okay to t urn a slottted/drilled rotor, but like regular rotors the rotor can only be turned so muc hbefore its worn out....I've turned my rotors 2 times in the 3 years I've had my car....and no problems...</TD></TR></TABLE>

Care to explain why not? The lathes I use will turn these rotors without any trouble. And there is nothing special about them.

 

hybrid....so any lathe can do it?
Any advice i should give to the worker there?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cee_mon &raquo;</TD></TR><TR><TD CLASS="quote">hybrid....so any lathe can do it?
Any advice i should give to the worker there?</TD></TR></TABLE>

We use Aamco lathes and I have been told by my teacher that there should be no problem turning a cross drilled or slotted rotor. I have never actually turned one to this day, they aren't that common in our shop. Just a few things to consider. With slotted, obviously each time you turn them you are loosing some of the effectiveness of the slots. Granted it shouldn't be much, eventually they will need to be discarded. The drilled ones I am not a fan of. They are much weaker then stock units and more prone to cracking. I am sure you will find 50 people who will be happy to tell me I am full of it, but fact still remains... If you get em hot enough, and just happen to hit some water, they WILL crack. The more you machine off them, the less heat they can transfer so they will only get "weaker" in this aspect. With those two things in mind, I see absolutely no reason why you couldn't turn them on any ole lathe. Assuming the dude doesn't try to take .010" off each side in one pass, it shouldn't cause any issues.

 

I called powerstop about this when I got my rotors...

YES you can turn them... on ANY machine...

I asked not only the people at stillen and summit (ordered fronts and rears at different times) but I called powerstop directly (powerstops are just brembo's with a cad coating)... THEY CAN BE TURNED ON ANY BRAKE LATHE. They recomended taking off only a small amount of material at a time and to use the slowest setting...

But it's fine to turn them...

As said do NOT lathe them past the chamfers in the crossdrills OR the rotor to hat area...

Oh but ALL 3 said you should never have to cut them... and if they do warp and you bought them new you can get new replacements for free.

 

well i bought them used....and was gonna turn them just to have a good starting block, but he said that they werent warped at all...should i get them turned still?
They look to be in decent shape...acouple little cracks but nothin much.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NonovUrbizniz &raquo;</TD></TR><TR><TD CLASS="quote">I called powerstop about this when I got my rotors...

YES you can turn them... on ANY machine...

I asked not only the people at stillen and summit (ordered fronts and rears at different times) but I called powerstop directly (powerstops are just brembo's with a cad coating)... THEY CAN BE TURNED ON ANY BRAKE LATHE. They recomended taking off only a small amount of material at a time and to use the slowest setting...

But it's fine to turn them...
</TD></TR></TABLE>

Yep, a lot of places don't like touching them because they look at it like this. They figured you bought after market rotors because you concerned about your brakes and you probably want a little better braking, well if they do resurface the rotors and something happens when you try to stop, they know there gonna get heat for doing it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cee_mon &raquo;</TD></TR><TR><TD CLASS="quote">well i bought them used....and was gonna turn them just to have a good starting block, but he said that they werent warped at all...should i get them turned still?
They look to be in decent shape...acouple little cracks but nothin much.</TD></TR></TABLE>

Dude... NO. If they are cracked then why are you messing with them? Cracked rotors are NOT safe to use. Save your money and buy either some new ones or something else that isn't cracked.

You don't always turn a rotor because its warped. Rotors can be dished, warped, rusted, etc. Usually, light rust will simply require a few brake applications to remove. But if the rust is excessive, then I would turn them. In any case, if you plan to get these rotors, I would install them on the car and then check for excessive latteral runout and parallelism. If they check out and the surface of the rotors does not appear to be damaged or heavily rusted, I wouldn't turn them. You shouldn't just turn them just to turn them.

 

here are some pics so you guys get an idea of condition...

 

It's possible. I had cross drilled and I had them machined. Came out fine. Stopped pretty good too.

 

run your fingertip over the rotor and if you feel little grooves across the disk, then i would have them turned. at the car parts store where i work we turn rotors and i asked my co-worker and he too said it shouldnt be a problem....besides, i doubt that all benz dealerships just give out brand new rotors to the owners who warp them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Cee_mon &raquo;</TD></TR><TR><TD CLASS="quote">Is it possible to machine down cross-drilled rotors?

Modified by Cee_mon at 4:33 PM 11/17/2003</TD></TR></TABLE>


i have experience with cross drilled/slotted rotors. you know what i found out is that they could be cut, BUT not a lot. only a few thousands or so. seeing that they have a REAL bad warpage problem i would not cut any drilled and slotted rotors and put them back on my car. now on the slotted rotors, the slots are cut into the rotor to the max. thickness. now what i mean by that is after you start cutting the rotors the slots start disappearring. and when they disappear, the rotor thickness is way to thin.
so if it is done, i would say no more than 3 or 4 cuts at 1 thousand's a cut. if you go more then 1 thousand at a time, you will destroy the rotor. i know this, because i've been there done that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by func-tion &raquo;</TD></TR><TR><TD CLASS="quote">Im not saying that im right. So dont flip when I say this.

I have turned a set of crossdrilled and slotted rotors with no problems.
I was simply told that once you get to the bottom of the chamfering of the holes its time to toss the rotors for new ones.
Heres a pic of them and they are still stopping strong btw.

EDIT: Sorry I forgot to mention when I turned the rotors I removed very little material. Enough to take off the rust from being stored for so long from the previous owner and there was a couple small lines. I dont have the time too look right now but I bet brembo has this question in there FAQ section.

yumm if thats an nrs &gt
Modified by func-tion at 12:47 PM 11/17/2003</TD></TR></TABLE>

 

hmMm good posts i had been wondering this the past week or so it just popped up outta nowhere.