Brake rotors and pads

Hi guys, I have a 2006 CS with 58,000 miles on it. My brake wear indicator went on, but I've been procrastinating and did not change the brake pads, so I've been driving for about 2 months after the indicator went on. In talking to Porsche dealers, they mentioned that in addition to getting the brake pads changed, I should also get the rotors changed. What is your opinion on this? Because, even with the brake wear indicator on, I have not had a problem with braking. My only concern is if I totally wore out my brake pads, and went metal to metal. Obviously I would prefer to conserve money, but not at the expense of saftey. So do you guys think that I need new rotors? Also I have read here that for one time, you can turn your rotors instead of getting new ones. Thanks for the advice guys.

I just had my pads replaced at 55,000, and had the work done at a repudable Porsche indy shop near here. The mechanic there I trust the most told me my rotors were good for another set of pads. If you run your finger on the rotor, you can feel the wear. I'd suggest you find someone like that to ask; he can see if you drove metal-on metal. Your 58,000 might have involved more braking, more abrasive pads etc than mine did. Having driven after the warning went off likely means you should get new sensors too. After 58,000, probably it's good to replace sensors anyway. I found OEM sensors on ebay and it was only $50 for all 4 shipped. Some guys who always check their pads roll without sensors, but it sounds like you should not. Turning the rotors is frowned upon, because the extreme wear creates the risk of rotor-shattering, which could be catastrophic. Additionally, if you look closely you will likely see small cracks in the rotors.

A very common question, a quick search will turn up a bunch of threads... http://www.planet-9.com/cayman-boxster-tech/29744-pads-rotors-must-replaced-together-yes-no.html http://www.planet-9.com/cayman-boxster-chat/49163-how-much-brake-job.html http://www.planet-9.com/cayman-boxs...ster-problems-complaints/29059-brake-pads-rotors-change-after-10-000-miles.html Measure the rotors to make sure they have enough meat left on them but my gut feeling is that at almost 60K miles, it may be time to replace them.

+1 I have over 70K on my Boxster w/ 10 DEs and still have the OEM rotors. I had my mechanic check them at my 60K service and he said they were fine.

You'll get a bunch of opinions, but I'll weigh in anyways. You should always turn or replace rotors with every brake replacement, no exceptions. If the rotor has enough meat on it, it may be turned, but to no less than the minimum refinish dimension (no, it won't shatter or distintegrate if it is turned to the minimum refinish dimension). Turning will provide the pads with a fresh surface that does not have hot spots in it and that is both straight and parallel. This will provide the best pedal feel, braking performance and will eliminate any pedal pulsation. From prior experience, in general I found that most German makes had rotors that could be turned once. The second brake replacement usually required replacement. spm, cpa

Unless you want to follow the advice of the dealers and just replace the rotors, measure the rotors' thicknesses and if they are above the legal minimum and by some amount (approx. 1mm) you can elect to leave the rotors in service and just replace the pads. I have replaced just the brake pads on my Boxster now more than a few times and have every time had a 2 to 1 ratio. 2 sets of pads to a rotor. But I check the rotors to make sure they're thick enough and by thick enough that the rotor thickness is about a millimeter thicker than the legal minimum. Sure, some experts recommend replacing rotors along with pads. The claim is this is the price of owning a high performance vehicle. There is some truth to this, but I have managed to obtain satisfactory results by replacing just the pads. But there are some things to consider. Both rotors must be in good shape, have sufficient thickness metal and not be severely grooved, or worn unevenly. The rotors should not have any signs of overheating, cracks, and should the brake pedal should not pulse while braking. If you find one rotor bad then you should replace the one on the to other wheel. IOWs, replace rotors in pairs. After replacing just the pads the brakes must be given a bed in treatment. This consists of on a suitable stretch of road taking the car up to highway speed and applying the brakes rather hard. Not hard enough to cause tire squeal or ABS action but hard to enough to really slow the car down and get the new pads hot. Slow the car from say 70mph to 20mph then release the brake pedal and accelerate the car back up to 70mph then repeat. Do this several times. Each time you should feel the brakes bite harder. I have found 3 times sufficient. Very important: Do not bring the car to a complete stop after the last braking episode until you have driven the car long enough for the very hot brake hardware to have cooled down. And you have to be prepared to bite the bullet and replace the rotors and possibly the new pads if the new pads and old rotors don't bed properly and braking action is not acceptable or there are other symptoms that you can't live with like brake squeal. Also, if you track the car you might find the while still thick enough rotors have enough metal to be legal being thinner they can't toloerate the braking track usage subjects them too and new rotors and pads (maybe "track" pads too boot) are required. Sincerely, Rockster.

When I ran through my first set of pads on the track in my 2.7, the dealer would not sell me pads without rotors. Sight unseen. So I went somewhere else. They always recommend changing both, and if you are only on the street you have to consider if the rotors will last through the next set of pads you definitely need now. My dealer wont replace wiper blades unless you get a new windshield, also. They are very concerned about my safety, and it is impossible to argue that old glass is safer than new, perfectly clear glass.

+1 on the 2 to 1 ratio.

If you turn the rotor you remove mass which is not good for braking. New pads will seat into light grooving on the rotor. As a result the length of line increases. So you end up with a bit more friction surface for the same swept area. For your own peace of mind you might want to check the rotor for min thickness.

Dave et al: Here's the thing. Dealers like replacing the rotors too because 1. More money, obviously. 2. New rotors are flat, the same as new pads. When you use new pads and rotors, the break-in is very easy and the pads generally don't get overheated. New components also have a lower chance of making noises etc. Those brake noise complaints drive dealers nuts! THAT'S why they always replace the rotors too. Turning perforated rotors is very hard on the cutting tools and can be hard on the rotors too. It might be possible to grind them if you have the right machine AND if the rotors aren't too thin. If you want to put new pads on old rotors and the rotors are thick enough, make sure you break in the pads extensively before using them hard. The high areas of the rotors will contact the pads first. If you use the brakes hard while only a small bit of the pads contact the rotors, the pad material can burn at these high spots while the low spots do nothing to stop the car. You have to take it easy until the pad surface fully mates with the rotor surface. If you take the time, they will work great. The more grooved the rotors are, the longer this surface mating takes. Find an empty road and do low speed braking, not to a full stop, and then keep moving so the brakes can cool again, then repeat. At the pedal begins to feel firmer, you can increase your speed a bit and keep cooling the brakes between braking events. Eventually, they will feel as firm as the old pads. Then, you can go home and park the car and use the brakes on the street in a normal way. Don't push the car for a while just to be sure the surfaces are fully mated. :kiss:

Good stuff guys, thanks for all the informed responses.

There are pros and cons to turning rotors. It removes some of the surface, so it shortens the life of the rotors a bit. On the other hand, replacing pads but not turning the rotors can cause brake squeal. I'm willing to live with some squeal to prolong the life of my expensive rotors, but the average customer at a dealer is not willing to put up with brake squeal. You get less surface area contact when you replace pads but don't turn the rotors, at least until the pad beds into the rotor. I think most dealers CYA on this, to prevent a lawsuit where someone claimed that loss of braking ability due to less surface area is what caused their accident. Unlikely, I know, but this is a lawsuit happy society, and we must all CYA. Dealers have to do this stuff "by the book" or they open themselves up to lawsuits.

Sooo many reasons not to go to a dealer for service. This is why I buy used and split the work between myself and my non-dealer shop. On a decently reliable car like the Cayman S, a warranty is just a way to scare you into overspending at the dealer. They have their place, but it's an infrequent sort of thing for me. Turning rotors with holes in them is tough on the turning tool and on the rotors. They need to be ground, changed or just left alone when you change pads. Depends on their condition. The "less contact surface" that Downshift talks about can cause the part of the pad that does contact the rotor to get hot enough to burn the compound, glaze it and also warp the rotor if you don't bed the pad in carefully. Another reason the dealer insists on rotor replacement. CYA in addition to pumping up the sales numbers!