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Should new rotors be cut?

Joined
28 July 2004
Messages
123
Location
Cedarburg, WI
I purchased a break kit from Dali. Just an OEM size but cross drilled and slotted with Project Mu pads.

I called Acura of Brookfield and talked to John Vasos about getting them installed. He recommended that I have them cut even though they are new. I thought, hey he knows better than me. I was a bit dismayed that it costs $140 to have 4 rotors cut, but I guess it is what it is.

Anyway, do y'all think this should be done? Or, is it a waste of $140 and any warping that the rotor has should be diminished if they are bed correctly?

Thoughts/comments?

BTW, the price I was quoted for install of all 4 was $140, then $140 for the rotor work and $140 to have the system completely flushed (ABS as well). Does that sound like a decent price?
 
Have you spoken with Mark Johnson about this?

I don't think he advises that for his rotors, at least not when I got my set from him a few weeks ago...
 
There is generally a specification detailed by the manufacturer on the run-out of rotors. If the run-out is beyond the manufactures limits, rotors are cut or "trued" to fall within the manufacturers specification.
 
I would not cut them. I believe that rotors are usually ready-to-install when new. Plus the fact that they are drilled/and slotted, they should not be cut anyways. I have seen new rotors with problems having extreme run-out which caused pulsation, but that is only with the cheaper no name parts. A good brand like Brembo for example should be fine. I would second guess about the Taiwan stuff. Good luck
 
MarkB said:


I’m guessing he means “turned” (on a lathe) ? To blueprint them.
You could check them for run out and warping with a dial gauge (like it shows in the manual) once they are installed if you are paranoid but like everyone is saying they come from the manufacture ready to go.

Regards,

Patrick
 
I've never heard of the need to turn new rotors.

Brocz said:
the price I was quoted for install of all 4 was $140, then $140 for the rotor work and $140 to have the system completely flushed (ABS as well). Does that sound like a decent price?
Yes. At their current labor rate of $92, that's 1.5 hours for each task.
 
It's possible it has a coating on it that needs to be cleaned off with brake cleaner.
Following that, you can "condition" the rotor surface for quicker pad bedding in by putting a little green burnishing disc on a cordless drill and knocking the shine off of the friction surface. Ive never heard anyone recommend turning slotted/drilled rotors. The bits on the brake lathe would skip and make the whole machine hop.

Harold
 
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