How often does the retaining bolt break when people replace their rotors?

Brought the Boxster in for a rotor replacement and a retaining bolt broke. I did the job myself four year ago and broke one of the four bolts... it was a pain so this time I thought i would let the "pros" do it...and they broke a bolt. So I ask... does this happen a lot?

The caliper bolts break more often than the retaining screws.

OTOH [www.autohausaz.com]

I've only had one car with rotor retaining screw issues, and that car had salt-water incursion in its garage.
The two screws generally come out fine if you first break the rust with an impact driver.
Their only reason for being is to align the rotor in place because they serve no other function.
The lug bolts are the ones that secure it to the wheel carrier.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

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Racecar spelled backwards is Racecar

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"If you wait, all that happens is that you get older"... Mario Andretti

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if you get a lot of corrosion on your rotors bit of anti seize on the screw it will help when taking out the rotors

There is a slight rubbing of the emergency brake with the rear rotor now when I make a right hand turn... is there a way to fix/adjust that? The garage said to give it about 100 miles to see what happens, but that seems kind of weird...

If by retaining bolt you mean the small flat head screw that holds the rotor on to the hub when the wheel is removed I never had one of these screws break.

To remove a stubborn one -- before you rough the tool bit hole up -- Pedro's suggestion using an impact driver is a good one. Years ago I used one to remove stubborn screws from motorcycle engine cases.

When I did my Boxster's brakes I didn't have an impact driver. I used a hammer and a small flat head punch to just tap the head enough to break it loose so that it came right out. I had a good philips screw driver -- Snap On -- with good tip and treated to not be slick.

When I put the new screw in I only tightened it until it was snug, with the rotor having no play. I can't recall now if I used any anti-seize on it or not. I kind of think I did. Might mention if I did this is in the only place I used anti-seize when putting in new brake hardware.

It is important to use new screws. When I did my Boxster's brakes I'd get a new brake hardware kit that included new screws and other brake hardware. I would also replace the caliper bolts with new ones. I did *not* use anti-seize on these.