Jupiterfish

had my car detailed this week and I noticed in the progress pictures they sent over the rotors were pretty rusty.
they typically don't get that rusty which I thought was odd. apparently the detailer drove the car "briefly" durning the week he had the car after putting the wheels on for a quick photoshoot.
I don't believe he drove it hard.
drove the car this weekend -now I have pulsating brake petal when stopping.
Also the typical brake dust has been replaced with rust colored dust which has never happened. Car has never been tracked or driver extremely hard, just back roads.

I have about 20k miles on the "big red" rotors and factory pads. time to replace everything? front pads are 20% left (no sensor yet) but rears are 70-80% left.
if I were to replace everything OEM do I just get the Turbo setup rotors and pads? the cars vin won't show the turbo upgrade.

thoughts?

evilfij

Brake hard a few times and see if it goes away.

Jupiterfish

tried that tonight - didn't work.

SC2993

Try some compressed air on the brakes and follow up with some brake cleaner. Repeat and then go for a drive, hit the brakes and see if the dust/debris clears from the pads a rotors.

pp000830

Pulsating brakes are from rotors that have become slightly warped usually from uneven heat cycling caused by sitting stationary with the foot on the brakes when the brakes are very hot from aggressive driving and the pads act as a heat sink for just part of the rotor.

At one time folks would turn the rotors down but since rotors only have a 0.020 difference in thickness between new and worn out and rotors have become inexpensive rockauto.com, folks just replace them. Also if a wheel is bent or even slightly out of balance it can reveal itself to a greater degree when the brakes are applied.
Finally, all rotors rust up. In moist weather or conceivably in the presence of detergent they may rust up a little more and so one should not be concerned about this as the rust is cut down with each brake application.

Rotors should last 70K to 90K on a street driven car.

Hope this helps,
Andy

ed devinney

I suspect the rotors were left wet while they worked, hence more rust than when the car sits in the garage. Not a huge deal, these cars are ... cars!

The closeup of the rotor face looks like the transfer layer of brake material on the rotor is uneven due to the rust, hence the brake feel issues. You can't hurt anything with another couple of episodes of hard braking from ~35mph or so. Really hard braking - make sure no one's behind you :-)

That said, your rotors have a bit of a lip and if the pads are really down to 20% you're not losing much money changing them out early. If the rotors and pads were newer I'd suggest using a sanding pad on a drill or even hand-sanding the transfer layer off the rotors, flat-sanding the pads a little to break any glaze, and then re-bedding the brakes. The rears may benefit from the sanding treatment. If you're taking it to a shop it might be cheaper to just replace the rear rotors vs sanding. Porsche factory pads are nice and quiet and probably worth the $. Rotors are expensive at the dealer, the $120 Zimmermans work perfectly well.

Bullitt44

There is a tool to clean rotors (drill attachment), dealers used this to repair rotors on cars that have been on the lots too long.

Also go drive the car and use the brakes aggressively (inspect rotor and pads for wear and damage first). This has been mentioned
but it can take some effort to have the rotors go back to what you expect.

**Best thing you car do after a car wash is drive it around the block, it also takes care of all the pooled water areas.

And lastly.....................PRETTY car!

Kitc2246

As already suggested I'd just replace the front rotors with Zimmermans from FCPEuro with their warranty and Porsche OEM pads. Pelican Parts is another good source. If you do it now no need to worry about replacing the sensors if careful when removing them. Buy a set of sensor anyway encase one cracks They are cheap from Pelican Parts.

You have uneven rust and pad deposit on your rotors. You have gotten your moneys worth, so just replace rotors and pads.

Old solid rotors would warp. Today's modern vented and drilled rotors seldom if ever warp even on the track.

Search bedding brake pads. Several high speed (65+) slow downs until you can smell the brake. It will even out the deposits and renew deposits on the rotors. You might tried a few high speed reverse stops first.

I would not waste my time cleaning the rotors with tools and a drill. As much work as changing the rotors and pads.

BobbyT

"All Porsche rotors have a 2mm wear limit from new, so if the discs start at 32mm replace them at 30, for the rears at 28mm/24mm you bin them at 26/22 respectively.
__________________
Colin Belton B.Eng."

Warped rotors are something of a controversy. Some enlightenment from an expert who says they are a myth here: https://www.apcautotech.com/getmedia...c-8-2018_1.pdf

Mark in Baltimore

+1 on pad deposits on the rotors. Pagid Orange pads were notorious for doing this. I remedied it by using a set of Hawk Blues, a quite abrasive pad, and solved the problem.

Although I've had rotor warping issues on another vehicle (past two Sequoias), I never, ever had warping with the 993s stock brakes. As Andy references, rotor warping can occur by having the brake pedal pressed down when the brakes are hot, but some cars are more prone to this than others. I resolved my Sequoia issues by using aftermarket rotors from Tire Rack (name brand but can't recall it).

Jupiterfish

thanks for all the good info, i will measure the rotors this week and also do some more speed braking on some back roads.
my indy dealer quoted me $400 each for fronts and $280 each for rears. i may buy my own and have them install.

pp000830

Sounds like a plan, be aware Porsche specifies the cap screws holding the front calipers on should be replaced any time a front caliper is removed. The calipers must be removed to remove the rotors. Lots of folks don't do this but Porsche wouldn't specify it unless they had some failure data to back it up so I would order the 4 cap screws for the calipers when doing the rotor change.
Andy;-)

Kitc2246

I think you are talking about the four long caliper bolts. Porsche replaces them. $5.50 each from Pelican Parts. They thread into the aluminum knuckle which can cross thread or be damaged from over torquing. Most who track cars replace bolts with Tarett brake studs. Removes the risk of thread damage. $125 per axle plus $25 for the brake line stud kit.