Pads & Rotors must be Replaced Together? Yes/No?

I know there's going to be differing opinion on this subject. That's why I'd love if people responded to the poll. I've put 35,000 kilometers on my car as a daily driver never tracked. I'm 2 years into a 4 year lease. I was told by the dealer I need to replace my front pads and that 'We always replace pads and rotors together (as per Porsche factory recommend.)" Now I'm guessing my rotors still have some life left in them, but if they're going to be shot by 3 years I might as well do them now since I'd have to do them before I give the car back at the end of the lease. Just wondering do you guys feel strongly that pads and rotors MUST be replaced together (perhaps so they 'fit' well together when braking with no 'ridges' from previous pads?) or do you think it's nuts to throw away perfectly good rotors with life still in them when all it is is the pads. Also, one other question. Is it safe to just run my pads down till the warning light comes on the dash? Or do I need to replace them when my dealer says too (like being overly cautious/trying to make a buck.) :thanks:

Pads and rotors do not normally need to be replaced as "sets". Normally, you would simply measure and inspect the rotors, and only replace them if they are close to the wear limit or if they have excessive wear, grooving or cracking. If you decide to replace the rotors yourself, remember that you will need new caliper mounting bolts -- Porsche says they are "one time use" only. As long as you only drive on the street, and not on the track, you should be safe to run the pads until the warning light comes on. However, if you wait that long, you will then also need to buy new wear sensors in addition to new pads. Normally, I would just replace the pads when they wear close to the sensors, but it's not that big a deal to wait.

Up to you on being cautious or not, and following the dealer's advise on when to replace the pads. I replaced mine about 100 miles after the light came on, and looking at it I could see at least another 500 miles of hard driving left on them. In terms of replacing rotors, I think it's BS... My dealer replaced the front pads without even mentioning anything about rotors (but then they know me).. But it's not the first time I hear on this board about Porsche dealers insisting on replacing rotors with pads. I mean your rotors COULD WELL BE shot, warped, cracked etc... But if they're healthy, there should be a lot more life left in them after grinding on just one brake pad.

Thanks for the replies so far. I know for sure I'll be buying my parts from Suncoast and then having the work done at an independent Porsche place rather than the dealership. I think I should have them inspect the rotors before I order the parts. I was curious because I know in cycling I usually replace my chain and cogs together so they mesh well rather than have an old worn cogs not meshing with a new chain. But who knows. Wouldn't it be nice if we could actually whole-heartedly trust the dealership and know that they have our best interests at heart? I wouldn't even mind paying more for labour if I knew they weren't gouging me on parts and possibly recommending things that didn't need to be done. Can you imagine? It would be so refreshing. Ah well.

Based on what I read in the service manuals it is not a requirment that the rotors be replaced at the same time as the pads. Rotor replacement is based on specific measurements are a visual inspection. The same holds true with the pads, but they are independent of each other.

I'm pretty sure if your rotors are thick enough you can get by with only changing the pads. Of course, you might want to have the old rotors turned--this might make you change your mind if the rotors are only marginally thick. So, no, you don't have to change rotors when you change pads--BUT, it depends on the condition of the rotors.

Can I ask which dealer?

Since the allowable wear on these rotors is only 2mm from new, it is not possible/advisable to turn these rotors. brad

You know... I get irritated when things arn't called what they are, and lately I hear more and more this called "bill padding".. It sounds so innocent...soft... and bordering on "accptable".... "Oh well... dealer padded the bill.. what are you gonna do...." It ain't no effing "padding"... It's deliberate deception to get into your pocket - the definition of a fraud. Somebody say it. Yeah yeah, it was just a dealer's recommendation.. Well, I understand dealers don't typically put it to customers this way - Porsche says you don't need pads, I think you do... And every time they say "we" I would be tempted to clarify is "we" - Porsche AG, PCNA, or Billy Bros, Inc....? All that said, so far I've been lucky to not end up on receiving end of such ****, which I know will not go well with my type of disposition. My dealer - Holberts, so far has been absolutely professional and accomodating in every respect. just venting....

+1 ....hate being lied to period! never mind insulted.

thePurist I completely agree with you, but there is wide disagreement on these things even on this site. Let me take two recent examples. My Porsche owner's manual and even a quick call to Porsche North America tells me I need only change my oil every 24,000 kilometers. My dealer (and many, many people on this site say it should be done every 12,000 to 20,000 kilometers.) I'm sorry, but I'll go by what the Porsche factory says. I get a nail in the middle of my rear tire. I can get it plugged properly and safely for $20 at an independent tire shop or pay $90 to get it plugged at one Porsche dealership (Pfaff) or pay close to $400 for a new tire/install (dealer prices of course) at Downtown Porsche in Toronto. Hmmm.. $20 or $400. In this case Porsche manual says no to plugging a tire, but Pfaff says they've been plugging tires for 20 years without a single failure. I'm comfortable with that track record. It's like black magic trying to get a straight answer. I guess all you can do is find an independent mechanic you really trust. Not that that's easy either.

Oh another one I love..... Wheels (not tires mind you - just wheels) off and on at Porsche Dealership $90. At Audi $60. At VW $30. In this case all 3 dealeships owned by the same company. I guess they must use special air guns and torque wrenches at Porsche . So silly all of this really.

Not hi-jackin your post bout pads and rotors but you brought up a somewhat inneresting point I've wondered about. Plugging tires, read you can't, wonder how many have with no issues. And if the dealers had their way it would cost ya $800, not the $400 mentioned as I've read you would need to buy a pair unless there was little wear on the good tire to match up with the new one? I do like the fact that Pfaff does plug if needed.

Replacing pads doesn't mean you need to replace rotors,however replacing rotors usually, but not always, means you should replace pads.

Never replaced rotors because new pads, in 30 years with any of my cars. My new Porsche is not going to be the exception. Also, never I have let any monkey turn my rotors either! It just doesn't make any sense (to me) to take away good metal. They worked fine with tiny little groves just before? It seems to me that these things have to be over-engineered by nature and there is a big safety margin in the design. It is a personal decision, how far to push the limit.

My Porsche owner's manual and even a quick call to Porsche North America tells me I need only change my oil every 24,000 kilometers. My dealer (and many, many people on this site say it should be done every 12,000 to 20,000 kilometers.) I'm sorry, but I'll go by what the Porsche factory says. This is the same issue I raised earlier last week. Why do the dealers say every 12 months for an oil change when the manual indicates 24 months. They just want you hard earned money!! My complaint was my Service Now indicator came on prematurely at exactly 1 year. According to the manual it should have come on at 24 months or at 20K. Again dealer mischief!

I forgot to mention, when I had my 05 Boxster , I had the the rear tires plugged twice for $12.00 at a service station. I never had any problems at all whith the the tires or the plugs thereafter. I do not track my car, it is simply for driving pleasure.

The rotor pad case is very much an "it depends" situation, and the current day auto repair business (dealers and independents) can't seem to deal with "it depends", so we get these binary rules. In an ideal world it really is a good idea to replace the rotors and the pads as a set. Rotors almost always develop grooves, and some pads, especially low-dust pads, can dig some pretty deep grooves. You can machine away the grooves by turning the rotors, but the advent of vented rotors has made turning nearly obsolete. Vented rotors are sort of like two rotors in one, but each only about 1/3 as thick as the rotor itself, making them pretty thin. Machine away 2-3mm of metal and what's left may warp from heat, spawning "comebacks" from the brake pulsing that results. I think many of us have replaced the pads without replacing rotors or machining the old rotors, and had no problems. I've probably done it fifteen times over the years (maybe more) and I had a problem twice. Both times on BMWs,with those massive single-piston calipers they use. The new pads squealed like baby pigs, and the only cure was new pads and rotors. That's right, once you groove the pads with old rotors you're done, you gotta buy new pads. Squealing happens, and most people hate it, and the only practical cure is a redo of the brake job. So, what do we get? Rules that say no pads changes without new rotors. I'm actually pretty thrilled that my CS rotors are showing no wear or grooving at all after 5700 miles. No cracks either. My Benz rotors are shot after 20K miles, and I have a manual trans car. The automatic versions often eat rotors & pads after 10K miles, and, BTW, they're essentially the same brakes as in the CS. Tire repairs are in a similar state of disarray. I've been plugging my own tires for years, even runflats, and I've never had a problem. Not even one leaker. Zillions of independents repair some tires, but not others. Then there's Porsche . No repairs. You can't even mix N-specs. Expensive? Too bad. It's a Porsche . I love it. :kiss: I know some people like to blame attorneys for all of this, and perhaps they play a role, but this lack of risk-taking by repair shops and dealers is OUR fault, IMHO. The mentality that a repair must be perfect the first time and forever or the shop is incompetent is the cause of all of this ***-covering behavior. That's another reason I to do my own work. Then I know who the incompetent mechanic is and where to find him.

Thanks for the opinion on plugging tires. I'll put a plug kit in the front compartment along with the gel and air pump. Most of my driving will in slow (city and highway), anyway.

I hope my Cayman is better than my Grand Cherokee Jeep in the brake department. I have to get the rotors turned more often than the pads replaced because of their tendency to warped and may the brakes pulse before the pads wear out. Who has 60K to 80K experience with the Cayman ? How much does track versus street use make a difference?

One of the great things about Porsche is they can back up their "smack" talk. High performance. Check. Some owners (or people who lease) however try to save a couple of dollars and avoid replacing tires by plugging them which equates to benching your starters on the Celtics and hoping to win. Reminds me of the folks who don't want to spend $50 on a battery tender and wind up spending $300 on a new battery. And I always wonder about the disclosure given when the car is returned on a lease or sold..do they say "oh, the tires have been plugged" or "I'm out of here"? Paying the premium for a Porsche with no intention of ever using its capability also seems unwise.

??? Plug = free (experienced with no bad outcomes on other vehicles); new tire = $250?? (or pair = $500) That seems more than a couple of bucks??? And, I'm not competing, particularly against the Laker caliber players. And, since I drive my Cayman regularly, I'm not in the market for a battery tender . Guess I'm in the wrong crowd. Or, I'd prefer to believe -- it depends on what you are doing with your Cayman -- racing or mostly driving to work and dreaming about running fast. Is the club mostly racers?

Don't think your in the wrong place cuz I have had nothing but good karma here, lots of info from some sharp cats. I aint speaking to or for anyone because it infuriates me to no end when others try to speak on my behalf and have no clue what I may have meant, or may be thinking but insist on putting their own spin on it, could be anything. I think I see where Sante Fe is coming from in my short time here, look at his post count, he's seen and heard it all. Again I am not trying to read minds but you do see people bitching about cost's and Porsche and then maybe do things on the cheap, then come here and whine.......tada, add it to the ongoing list LMAO. BTW I don't track but there are a ton of guy's who do and don't.

Thanks. Also, I should have asked about Cayman handling if a time blows, say on the the highway???? If the Cayman becomes imposssible to control, then a plug becomes much more of a risk.

That really depends on a lot of things. Fast driving on my mountain no run off roads or skimming down the expressway for example. For the casual driver on a long curve free straight you have good control. For a sudden explosion on a curve with no run off and a hundred foot drop not so good. I'd prefer to have the ability to not have either event in my life so I don't mind a few bucks to prevent that happening.

Also, thanks. "It depends," with appropriate caveats, seems to be a good answer!

Lots of good responses here. Thank you! :cheers:

The factory service manual has rules about when to replace pads, and rules about when to replace rotors. Pads need to be replaced when they get to about 2mm in thickness. Rotors need to be replaced when they are thinner than the minimum, or cracks connect the holes or reach the edge of the rotor. There is NO rule in the service manual that says "replace rotors whenever pads are replaced." Such a rule does not exist. If a dealer tells you this, they are after your money, period.

I voted to replace the rotors at the time of pad replacement. Would I actually do that? It would depend on the circumstances for making the pad replacement. If I was off-track and driving until the pads were reaching their full-life of wear. then more than likely the rotors will show signs of wear. If not cracks, they could/would have wear grooves. And any rotor with grooves will not interface with any pads in the same, highly effective, manner as new pads and a properly surfaced rotor. And if you get any rotor surfaced, it will remove material from them. And when you do that, you will change the point in time when your braking system will be at its minimum from what it is when new. Let's visit drum brakes for a minute. When you turn a brake drum, it becomes necessary to get over-sized shoes, as the drum becomes undersized after machining. And to not do that, makes the drum arc different than the shoes. And even after "wearing" in, standard shoes would still be thinner, and fail sooner, as a result. The same think will happen with pads. If the full thickness of a rotor is x, then the entire thickness of the pad y + the rotor x will be less if a rotor has wear or is machined. The next time when the pads approach 2MM. the brakes will not be as effective, if the rotors are thinner. That is why all rotors have a minimum machining thickness in the first place. If I have ANY wear on my rotors, I will normally replace them when changing the pads. If the rotors are thick enough to permit machining, then I would do that. Typically, cars with serviceable rotors, like Porsche , make it cheap enough to just replace the rotors, as the cost of machining them is most of the price of the rotor, especially when considering taking the part off and to a machine shop. If the rotor also contains the hub, like an old Ford 4wd, then that's a different story, as machining is cheap compared to replacement. If you have a car with world-class brakes, why would you do anything that would make them any less than that for a few $$?

Regarding your first point, about why there is a minimum thickness to rotors, this is contrary to what I've been told or read over the years. I was always told there is a minimum thickness for structural reasons, in that beyond a certain wear point you risk cracking or warping a rotor when the rotor temps go up. As for your comments about "a few $$" and the cost of turning, this isn't going to be the experience of a Cayman owner at a dealership. I haven't priced a rotor replacement, but based on just the parts cost I'm guessing a dealer would charge well over $500, over and above the pad costs. Suncoast wants $290 just for a set of OEM CS front rotors.

Do rotors last longer than pads? I think so. No cracks, good thickness... I'd wait. Short story... in '68 I bought a new 245s Volvo wagon. After ca 1500 miles, the left rear rotor came loose(?) and gouged the disk. Brakes not covered under warranty then, the dealer said I needed a new rotor. I was poor so I said "screw it!" I later replaced the pads a number of times (did it myself, very easy) and put over 110k miles on that gouged disk before I traded it in. Now I seriously don't recommend doing this today, but dealers do make a lot of money on service. I'd look for an experienced independent Porsche mech to assess the need before replacing the rotors based solely on a "dealer recommendation" Luckily, I have such a local guy to do that. His oil changes are only $90 for Mobil 1 and a Porsche filter, including labor.

Not hi-jackin your post bout pads and rotors but you brought up a somewhat inneresting point I've wondered about. Plugging tires, read you can't, wonder how many have with no issues. And if the dealers had their way it would cost ya $800, not the $400 mentioned as I've read you would need to buy a pair unless there was little wear on the good tire to match up with the new one? I do like the fact that Pfaff does plug if needed. I got a nail on a new tire recently. The dealer noticed that when I took the car for the 2 yr service and they plugged the tire for 50 bucks. I had a coupon for 300 so I didn’t mind

I think most people believe that rotors last much longer than pads. But there does come a time when rotor and pad wear "syncs up" and they get replaced together. Like most, unless the rotor is worn below the minimum, I replace pads only. Eventually, though, the rotor reaches or gets near the minimum. When the rotor gets near the minimum, and the pads are also near their minimum, I get both replaced together. I think this is pretty typical (and obvious!). In this case, both are replaced together, but not because they always get replaced together. They are only replaced together because both are close to the minimum wear.

:hilarious: The dealer? I guess Porsche's directives are optional! :hilarious:

My local shop just removed my OEM wheels and mounted and balanced tires and wheels that I brought to them, and installed them on the car for $50 total!