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Re: Is it true that since our brake rotors are drilled, they shouldn't be turned- but fully replaced?


Expect the best, and accept no substitute.

Products for your Boxster, Cayman and Carrera.
I love learning about how our cars are different. I'm at the service department today getting ready to store the car for the winter.... very sad day indeed. sad smiley
... does not promote turning rotors. They specify that they need to be replaced.
If your rotor's surface is so bad that it should be rectified I would replace them.
Nevertheless, if you are using a complimentary pad for that rotor, its surface should wear very evenly and would allow you to run 2 full sets of pads.

Indeed, it's a sad day when you have to store your Boxster for months.
In my part of the world, we cherish this time of the year, when we can finally put the top down and enjoy a little cooler weather.

Happy Boxstering,
Pedro

Pedro Bonilla 1998 Boxster 986 - 280,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna
Need I point out that us Cayman owners can only happily roll down our windows drinking smiley



Edited 1 time(s). Last edit at 11/03/2017 02:04PM by Gary in SoFL. (view changes)

"A mile of highway will take you one mile. A mile of runway will take you anywhere."


Pedro Bonilla 1998 Boxster 986 - 280,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna


"A mile of highway will take you one mile. A mile of runway will take you anywhere."
... unless they are warped, and I've never warped a rotor, even with heavy track use, why would you turn them? Typically the pads wear to the rotor. New pads will quickly seat to them too. I avoid removing material - it just hastens wear.

Grant

Grant gee-lenahan-at-vee-eff-email-dot-net
You're probably mistaken.
Quote
John from MN
I love learning about how our cars are different. I'm at the service department today getting ready to store the car for the winter.... very sad day indeed. sad smiley

The rotors can be turned -- although Porsche may have something to say about this in the factory service manual (I don't recall seeing anything but that doesn't mean it isn't in there) -- but the presence of the holes -- they are not drilled I believe but cast in but it makes no difference -- can cause problems with the turning. If cast in the cast iron scale can chip the carbide tool. Even if no scale is encountered the tool bit doesn't like the interrupted cut. This can leave ripples after each hole unless the brake lathe is a pretty rigid machine tool and my memory is they aren't. They worked fine for rotors with no holes -- I used to have the no holes rotors on my Dodge pickup turned -- but for drilled/holed rotors, not so much.

Also it is extra work to avoid removing too much metal -- there is only 1mm (per rotor surface) to play with -- so the tech would probably have to take more than one cut/pass to sneak up on a full clean up without removing too much metal. This adds labor cost. And if he gets to the 2nd rotor and finds it doesn't clean up the labor of resurfacing the 1st rotor is lost because both rotors have to be replaced as pairs.

Some machines use a grinding wheel and not a single point turning/facing tool and I have seen a setup that can grind rotors on the car.

But there is still the cost of the brake rotor turning equipment, the setup time, the clean up time, the risk both rotors won't clean up before going undersized, and then the chance the customer will encounter a problem -- even if not due to the resurfacing -- and come back. With higher labor costs the cost of replacing vs. turning gets to be about the same.

So replacing rotors is just easier, less work with lower labor cost, less chance of a comeback and if the customer does come back the odds are the new parts warranty covers any hardware problems.

However, even if replacing just the pads, the rotors often do not need turning. In fact if they do need turning they probably should just be replaced anyhow.

With my Boxster a couple of times when the pads have worn out -- the brake wear warning light comes on -- after checking the rotors and finding they still have some metal left I've replaced just pads and as long as the rotor surfaces ain't too bad -- and they ain't bad in the case of my cars -- the new pads seat/bed in pretty quickly -- I do a bed in to expedite this process -- and braking action is quite good indistinguishable from braking action after fitting a new set of pads/rotors.

A problem though replacing just the pads is often before the 2nd set of pads are worn out the rotors are worn undersized -- too thin -- which isn't good. It hasn't caused any problems for me and my car but not everyone could be as lucky as me.

More recently when the pads are worn -- the brake wear warning light comes on -- I just replace or have replaced the pads and rotors. While the rotors might have a bit of "life" left it is not enough to worry about. Last set of front brake hardware lasted 51K miles.
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