Brake maintenance

With an upcoming DE, I have to replace my pads as they are below 50%. Today I called the dealer to find out how much they would charge and I was told that they replace the rotors at the same time. I thought this was unusual, as I usually just replace pads and sometimes turn the rotors. (I've already searched the similar threads. ) Anyway, they want $1450 to change pads, rotors, and sensors all the way around. I've currently got 18k miles with 2 track days. Given I've done hundreds of brake jobs on other types of vehicles, I'll be ordering the pads from Suncoast and replacing them myself. The replacement timeframe and pricing don't seem extraordinary given other threads around here. The dealer did say even if I didn't replace the rotors this time, it would be *very* unlikely that they would make it past a second set of pads. I've seen the articles and what not, but my questions are .... Are there any Porsche specific tools that I would need to make the job easier? Do most folks use track pads on track days and switch back on daily drivers?

no special tool, use a plier to pull the "U" shaped safety pin, the rest can be done by hand. i run track pad on the car full time. can be noisy at times. takes 1 hour or less to replace pads, so you can swap back to oem if you like.

I've read that using track pads will force me to replace the rotors more frequently. Is that correct? How much more frequently?

Did they say what's wrong with the rotors? Do you see any cracks in them? Are you getting vibration under braking? I wouldn't think that 18k miles with only two track days would cause that much rotor wear. Yes, the higher friction of track pads does cause rotors to heat up more and eventually start cracking. When the cracks get too long (over 1/4") and/or go out to the edge, it's time to replace. Very high heat can also cause warping (never put the hand brake on when parking after a track session). How frequently you'll need to replace rotors varies, but I have 9 track days and 8 autocrosses on mine and might get through this year with the OEM rotors. There are some very small cracks in the front rotors, so I'll be checking them frequently.

They said that most of the time, they just replace the rotors when replacing the pads. I'm not having any problems and I can't see any cracks, but I have to replace my pads to continue my participation in DEs. It sounds like a scam to me, which is pretty disappointing. Thanks for the comparative info.

Sonny Does the dealer's outrageous price quote include the Vaseline? Replacing your Porsche pads will be the easiest pad replacement you've ever done. If you'll be tracking regularly & thus inspecting your pad wear, you can cut & short circuit the wear sensor wires which speeds up pad replacement. You do not need track pads at this point & won't for a while.

Thanks for the response (and humor) Dan. I'll order the stock parts from Suncoast and get them in this weekend. Now I just need to figure out what I need to flush my brake fluid. I'll probably use the method that you talked about on the other thread with the pressurizer and the bleed bottles. I've always used the old fashioned route and want to give my wife a break

You most likely don't need rotors. Sounds like dealer is working you over the coals for more money to me What they said about "we always replace rotors when we replace pads" is ridiculous!

They replace the rotors for a couple of reasons the most important is liability. And also if the rotors are not smooth you will not have the best braking until the pads wear to the rotors. The prices at suncoast are not bad I would do the rotors also and if you have not and are going to bleed the brakes change to stainless brake lines.

I knew i needed pads for my BMW (40,000 km), but when i took my car in for the stage 1 inspection, the service rep told me i needed pads and rotors. I told them to change just the pads. They went on and on telling me that i would need rotors and that i would be in again..yadda, yadda, yadda. I drove the car another 10,000 km before selling it.

I think they do this because when most Porsches, driven by your average driver who doesn't do DEs, need pads its probably got 30-40k miles or more on the clock, and more than likely they do need new rotors, by that time. So, that's their standard line - "pads and rotors." Most people don't change their pads when there's 50% left. As others have said, your rotors are probably fine, and since you're going to be down there changing the pads back-and-forth - you'll be up-close and personal with your rotors, and it will be easy to keep an eye on them. brad

Check out the articles section of this site - there's a great article on how to change the brake pads. Yes, racing pads tend to be more abrasive (in order to be more aggressive), and will tend to wear rotors faster. There are 3 reasons to replace rotors: they're cracked (any crack connecting two holes, or a crack extending to the edge of the rotor), they're worn down, or you're changing pad compounds. I don't know what the specified minimum thickness of the CS rotors are, and you'd need a micrometer to measure it anyway, but be aware that most manufacturers today don't add much meat to the rotors, so they get to minimum thickness fairly quickly. Porsche may be an exception. It isn't absolutely necessary to change rotors if you change pad compounds, but the bedding-in process for new pads involves physical changes to the rotors as well, so it's not a bad idea if you can afford it. BTW, does anybody know what type (brand) of brake fluid Porsche uses? The manual just says "approved Porsche brake fluid", or something to that effect. Is it DOT3 or DOT4? What's the boiling point? Until I change my fluid out entirely, I'd like to be able to top up the reservoir with a compatible fluid when I bleed the brakes.

An interesting article http://www.stoptech.com/tech_info/wp_bedintheory.shtml particularly the adherent friction info.

Does the Cayman use Steel Braided brake hoses or just the normal rubber ones?

Normal hoses but there are SS replacements available at a low cost.

Lots of brake places pull scams like this. If you've done 100's of brake jobs, why would you fall for it? I do all my own brake work, as I enjoy it, and the only car I ever replaced rotors on was a 280 ZX I ran the pads off of and seriously gouged the rear rotors (dumb college kid). That was 1988. In 1996 I had my wife call the local Jeep dealer to see about her brake shimy. They wanted $209 to turn the front rotors on her Grand Cherokee. I called with the same story and they wanted $100 (I guess because I was a guy). Then I asked why I should pay $100 when the local parts store turns 'em for $6 a piece. They told me the turning was nothing-they would do it for free even- it was getting them off the car that was so hard. I took them up on their offer and after spending 15 minutes popping them off the car I got them turned for free. We've put about 600K miles on cars since college, with the above-mentioned ONE pair of rotors replaced and ONE pair turned. Barring real evidence of cracks between holes or wear beyond the thickness limit (and except for the Datsun I've never exceed the thickness limit in any car I've had), NEVER replace your rotors. Replacing your pads at 50% is well, crazy too. If you really want to throw away the money, just send it to me as a consulting fee.

The "normal" rubber lines seem to be just fine for Cup Cars, but maybe those guys don't brake hard

You may think it's crazy, but it's required by many PCA Regions to pass DE tech inspection for a good reason - after 50% pad wear heat transmission increases dramatically resulting in a greater possibility of boiling brake fluid = no brakes, which is not a good thing. You can, of course, reinstall your under 50% pads after the DE for street use.

wpmjr - this is not crazy at all. Crazy is balling you Cayman (or any other fine machine) up in a heap when your pads are used up or your brake fluid boils! STLPCA is absolutely right, you should ensure at least 1/2 new pad thickness before a day at the track. As your skills increase and you start braking later and harder, you will be surprised how much pad you can use up in a weekend. Pad replacement is a easy job that serious track junkies should learn to do themselves, along with brake fluid bleed/flush before every track weekend.

Well, I don't doubt you because I don't road race. If we're talking autocross or street driving, it is crazy. Amazing how many road racers evidently populate this forum. When I went looking for aftermarket adjustable struts the explanation for why the choices were so few was that so few Porsche people raced. Go figure. Anyway the biggest point I have to make is about the rotors, but you and another poster chose to ignore that. I wonder why. And the dealer was making his recommendation based on street use, I assume, which is just criminal. Well, now maybe I should back up. Maybe Porsche provides a ridiculously short-lived rotor. Maybe 18K miles, or 1 or 2 sets of pads is all you get. I mean, this is my first Porsche, so what do I know? That would be pathetic compared to the corvettes and S2000's and Miatas I've raced, though. Then again I wasn't prepared for 10K windshields either. Anyway, you lost to a Z06 in autocross, right? C5 or C6? A 70 second course is pretty long. Was that just one lap? How fast was the FTD? Are you new to autocross? Evidently you also road race?

I just changed my own brakes pads and flushed the fluid. I got the pads from suncoast for ~$200 and the bleeder w/fluid from motive for ~$100. I switched to ATE blue so that I could see the color change. It took me about three hours, but if I did it again it would take me about an hour and a half. Wow that was an easy $1200 to save This car has to be the easiest car I have ever changed the brakes on. If you bleed using your significant other and not one of these motive bleeders, you are nuts. This is a great forum for all this info. By the way, a 3.5 inch putty knife does a great job at removing the backing plate from the pads. Thanks for the advice all.

Did you think I would mislead you?

Usually they are replacing pads and rotors after 30,000 miles or so. It is standard procedure for all dealerships. You can tell them, "Yes. I understand. Please just replace my pads." My rotors are perfect. I am NOT a DIY guy. I just changed my pads yesterday with the "help" of my best friend who is a DIY guy. He was there for moral support as it turned out. It is so easy it is ridiculous. The only downside is that you will become very cynical about dealership service. My friend is a gear head and he was laughing because it is so easy to change the pads on our cars compared to any other car he has worked on. Truly impressed by the engineering. I am on my third set of fronts and second set of rears after 7500 miles and between 15 and 20 DEs. The fronts seems to wear at near exactly a 2:1 rate compared to the rears. The sensors are $40 a piece from the dealership, so save yourself money and don't wait until the brake sensor activates...or change them asay after one pops to save the remaining sensors. Look under the "articles" section and check out the items related to brakes and brake fluid. All the info you need is there. I was in a bind and had to order OEM pads, sensors, and "silencers" from a dealership and have them overnighted for Saturday delivery...DOH! That was $470. My 2.7 didn't have any silencers installed in the rear, so I didn't add them. Now I know how easy it is and will shop around and buy some pads to keep on my shelf. Tools? A pin punch or wooden dowel that is small enough to punch out the retaining pin, needle nose pliers, a towel, a large screwdriver/ wrench (for wiggling the old pads back and forth to compress the pistons so you can slide the new ones in). That and a jack.

And wheel chocks. I'm going to do that myself soon. Thanks Dave.

Very good thread as I have run a few DEs and the latest pre event tech indicated about 40% left. How does one measure what's left, what is a new pad thickness?

You can eyeball it from the outside...but the best way is to buy a new set of pads. (You will eventually need them.) Then just pull off a front wheel and look into the caliper and compare how much is left on the pads versus the new one in your hand. New pads have (I am estimating) a half inch or more of material in front of the metal backing. If you replace your pads before they wear down enough to trp the disposable sensor, you save $40 per wheel...goood reason to keep an eye on them.

Almost thirty years ago, I raced SCCA showroom stock for a while. I quickly learned that a set of brake pads and shoes (the car had disc/drum brakes) would last one and a half race weekends. Therefore, I changed them after every race. Showroom stock is real racing; first guy to the checkered flag wins. You accelerate at full throttle up to the next corner, brake almost to the point of lockup and then get back all the way on the throttle again. Repeat every 20 to 30 seconds. During a typical race weekend, you would spend a total of three hours on the track. Dividing gives you between 360 and 540 hard, high speed brake applications per weekend. I don't know how hard you drive during a DE. If it is at all like the racing I described above, I think the 50% rule is wise. Remember that I used up 67% of my brakes in a weekend. Although they were no longer perfectly flat after a few races, I never needed to change rotors. The mechanic doing the brake job needs to judge the rotors on their actual condition, not just change them on an arbitrary schedule. Another thing I learned was to drive at least one hundred miles on new pads and shoes before racing on them. Until they seated properly, braking efficiency was substantially reduced. This didn't matter during normal driving on the street. On the track, it felt like severe brake fade. If you are only running autocrosses, you needn't worry about brakes at all. Runs are so short and slow that you don't significantly accelerate brake wear.

I just can't believe dealer profit margins on brake jobs. It's in the 500-800% rage. And it ain't just Porsche that does it... :crazy: After my first track day in the Cayman S, I blew through a set of front pads in 6 sessions (the car had ~4k miles on it). A bit of a shock, to say the least, especially after being able to get 3 race weekends or so out of the Spec Miata. A word to the wise - if you're an experienced driver, you'd be well off to get a set of race pads for track days. They'll wear slower when up to temp than the street pads by quite a bit. I could almost see the clouds of brake dust off of the stockers in my rearview... Cheers, Kevin

Break myths debunked: http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

When I called my dealer to have the brake pads changed I was quoted 2hr for the front and 2hrs for the back. My dealer charges $98 an hr! That would be nearly $400 just for the labor! I thought there is no way it takes 4 hrs to change brake pads. Did myself in about 1.5 hrs and it only took that long because I hadn't done them before! Sometimes dealers really try and take advantage of people.