•Q. I recently needed to replace my brakes, and the shop sold me on ceramic brake pads. The pads have a lifetime warranty, which is very appealing. I also was told that ceramic pads will generally prevent rotors from warping, eliminating the pulsating affect that one feels when braking with warped rotors. After making the purchase, I’ve been told by several people that ceramic pads wear the rotors more evenly, preventing warping, but they also wear the rotors far more quickly. In your experience, did I save money by going with ceramic pads? Or am I actually spending more money, both up front (on the pads) and down the road (on additional rotors)?•

RAY: Here’s the brief, sordid history of brake pads. The first pads were made out of shoe bottoms. My brother remembers sticking his foot out the door and dragging his shoe on the road until the car either stopped or hit something.

TOM: Yeah. That was last week, in my ’78 Fiat!

RAY: Brake pads in recent years have been made out of asbestos, other organic materials, semi-metallic materials like steel wool and iron and, most recently, ceramic compounds mixed with copper strands.

TOM: Each of these materials had its advantages and disadvantages. For example, asbestos brake pads were nice and quiet, but they caused lung cancer. Non-asbestos, organic pads were safe for humans but didn’t always stop the car very well. Semi-metallic pads performed well but made obnoxious brake noises and left black brake dust all over people’s wheels.

RAY: So the current state of the art is the ceramic pad, which seems to balance all of the criteria of brake pads pretty well. It lasts a good long time, stops the car well, dissipates heat quickly, absorbs noise better than metallic pads and leaves a nice, light-colored brake dust that’s a lot less visible and bothersome than the black stuff.

TOM: So, you got the right pads. That’s what we use on our customers’ cars these days, mostly to eliminate complaints about noise and dust.

RAY: When ceramic brakes first came out, I remember that the suppliers warned us against using them with cheap rotors, because they are harder than the older, metallic pads — that’s what makes them longer-lasting. But rotor makers have caught up, and we haven’t had any problems in recent years. So as long as you’re not buying your rotors from a guy in a trench coat who says, “Psssst!” I don’t think you’ll have to worry about excessive rotor wear.

TOM: As far as we know, however, ceramic pads do not prevent warping. If you misuse or overheat your brakes, rotors will still warp. It’s possible that the improved heat-dissipation qualities of the ceramic pads may help prevent warping to some degree, but you’re not going to be immune from warped rotors.

RAY: You will be immune from black brake dust and ear-splitting brake squeal, though. So congratulations on a wise purchase.

•Q. I have a 2001 Dodge Neon with more than 150,000 miles on it. Until very recently, it’s been an extremely reliable vehicle, and I’ve loved it. Lately, and at random times, however, the engine will not shut off — even with the key removed from the ignition and in my hand! I’ve already gotten a new key and replaced the entire ignition cylinder, but it happened again yesterday evening. Luckily, yesterday I was able to fiddle with the key a little bit and finally get the stupid thing to shut off. What could be causing this? At this point, the mechanics I’ve taken it to haven’t been able to identify or fix the problem, and I can’t find anything on the Internet. Each time it’s happened, my local mechanic has disconnected the battery, which made the car turn off. After that, though, it runs perfectly for maybe a couple of months, until it happens again. Any idea what could be wrong?•

TOM: You’re a lucky woman — you can’t get your Neon to stop. Most of our customers with Neons can’t get them to start!

RAY: You say you replaced the ignition cylinder. But that’s just the locking mechanism that the key fits into; it’s not the ignition switch itself. So you easily could have a bad ignition switch.

TOM: But before you replace the switch, try replacing the ignition relay. Rather than have a huge amount of current running through the steering column to the ignition switch at your fingers, the ignition switch signals a power relay under the hood. It’s that relay that actually sends current to the engine’s computer, which enables the engine to run. That relay could be faulty and sticking in the “on” position.

RAY: The relay probably costs 20 bucks, and it takes two minutes to replace. So start there, and see if that fixes your problem.

TOM: If not, then it’s almost certainly the ignition switch, because there’s really not much else that could cause this. But since replacing the ignition switch will cost you several hundred dollars, don’t do that until you’ve ruled out the $20 fix. Good luck.

Got a question about cars? Write to Click and Clack in care of this newspaper, or email them by visiting the Car Talk website at www.cartalk.com.