Tbred911

My brake light has gone on and I was thinking of just replacing the pads... is it true that rotors need to be replaced as well? somebody told me that aftera while the rotors have grooves in them that were made by the pads and fresh pads will cause considerable steering wheel shake if the rotors aren't replaced as well... the car has 43,000 miles on it and rotors are stock... any opinions?

ventoGT

When I got my brakes replaced around the 50K mile mark on my 996, I was told that the rotors needed replacement as well as pads, and that Porsche recommends this. I may have just been a sucker, but my maintenance on my lease was subsidised so it didn't end up costing me all that much more just to do it.

jetskied

Its not the grooves that will shake the car, but that over time the heat will make the rotar not staight and that will cause the shudder. Generally speaking if the car does not shake now it won't with new pads. However if the rotars do have considerable groove the braking efficency is reducesd and you can get brake squeel noise. The only true way to know if the rotars are done is to have the thickness measured and see if they can be resurfaced. Given that you have so many miles its probably time or close to it to replace them. Only a machine shop or brake shop can tell you if you do. The dealer will tell you to replace them because they will want to up sell you. Its hard to find a honest opinon out there.

PorschePRH

Depends how you have driven those 43K miles. But basically it comes down to rotor width and condition of rotors. The crossdrilled rotors can not be turned if I remember correctly, so if they are warped or gouged, you will have to replace them.

If they are true, and within size spec, just replace the pads.

You will only have steering wheel shake if the rotors are warped. The number one cause of warped rotors is improperly torque rotors, by the way. So make sure they are properly torqued by the people that do work on your cars (which is rare for them to do it right).

If your rotors have groves, you can still use them. The pad material is pretty soft and it will conform to the groves quickly. In my less rich days, you should have seen the groved rotors that I reused with no problem!

JimB

How do you torque rotors? They are held in place by two very small screws until you put the wheels on. Do you mean torquing the wheel bolts?

Rotors are cheap so you might want to replace them just to be safe. As I recall they are around $140 each and very easy to put on. There should be almost no labor if they are also changing the pads. Maybe 1/2 hour at most. You'll also need new caliper bolts.

It is unlikely that your rotors are warped. They can take a massive amount of heat. (to start a debate, many experts don't think rotors ever actually warp. The shutter is caused by deposits) They may be too thin or they may be cracking. Look for little cracks between the holes. If they are close to connecting or if any cracks are reaching the edge then you should replace them.

Just my ideas. They could be wrong.
Jim

1999Porsche911

I have not yet replaced my stock pads (48,000 miles), but I will probably throw on a new stock rotors when I do. They are cheap enough and easy to do. However, replacing them is not necessary as long as they are true, thickness within specs and minimal cracks around the holes.

Rasta

How much to OEM brake pads and rotors cost, if you decide to replace both? What would be the labor costs?

TurboMark

I am just going through the same decision process.

Cpa4S

Rasta: Car & Driver suggest in their long term test, that the C4S brakes will last the life of the car or 100k miles.

StephenB

I have had to replace both fornt and rear rotors on my 996 C2 due to wear below the minimum thickness. Both were below minimums at nearly the same mileage. I didn't make it to 100k as stated in previous posts...only about 95k miles and they were below minimums. No track, but a couple of autox. YMMV

Cpa4S

just a reminder that the C4S comes with the much larger turbo brakes; so not really comparable.

agio

What is said above is mostly great advise. However, I didn't see anyone mentioning small fractures that may appear near the holes (although I could have missed it). These cracks need to be watched carefully. If they become too stressed, the rotor could fail. Check them carefully and replace when needed...as has been said, they're not terribly expensive.

Riad

when do you need new rotors...?

If you take your car to Prestige Porsche then it's every time you need an oil change.

TD in DC

AFAIK, there are three main factors to consider:

1. width of rotor -- Porsche publishes specs on when rotors must be replaced. I don't have it in front of me but someone should be able to chime in.

2. warped rotor -- It is unlikely that your rotor will be warped if your width is in spec, but I guess it could happen

3. cracked rotor -- You should replace your rotor if the cracks on your rotor either (a) join two holes [or are more than 2/3 of the way to joining the holes] or (b) go from one of the holes to the edge of the rotor.

The rotors are about $100 each. Since you do NOT want to replace your pads and your rotors at the same time, I would not let a dealer do it. Buy them from suncoast or somewhere else and then replace them after your new pads are worn in.

Tbred911

Hey TD... thx for the info... I will inspect them tomorrow... I don't remember seeing any cracks as you describe them... the only thing is (and this may be normal) if you slide your finger from the center of the rotor to the top... there is a bit of a lip right at the edge of the rotor...

one of the tech guys (Porsche) told me if I didn't replace my rotors and just did pads... the steering wheel would shake violently... sell tactic?

it's funny... about 6,000 miles ago when I had the car in for an oil change the dealer wanted to replace pads.... you know the standard "lets' replace everything"... but they never commented on the rotors... now at 44K miles the rotors must be replaced... hmmm just 6K ago it wasn't an issue... I don't know...