Dear Tom and Ray:
A friend of mine at work and I have a disagreement regarding using the clutch on a standard-shift car. He says that keeping the clutch pressed in will wear out the throw-out bearing, and I say it won't. For example, he says that when on a hill, the smart driver will put the car in neutral and let the clutch out, keeping one foot on the brake, to save wear and tear on the throw-out bearing. I say keeping the clutch depressed won't cause wear and tear. Who's right? —Red
RAY: He is.
TOM: There are two common ways that clutches die. The most common is that the clutch disc wears out. That happens over time, due to the natural slippage that takes place when you engage the clutch to get the car moving. Eventually, the friction just wears out the disc, the clutch starts to slip and you need a new clutch.
RAY: This process can be greatly accelerated, however, if you ride the clutch — that is, give the engine too much gas and let the clutch out too slowly. We call this first-degree clutch murder.
TOM: The second most common type of clutch failure is when the throw-out bearing (also called the release bearing) fails. That's the bearing that pushes the clutch plates apart when you push in the clutch pedal to change gears.
RAY: Used correctly, the throw-out bearing will last much longer than the clutch disc. But if you sit at red lights with your foot on the clutch pedal all the time, you can wear out the throw-out bearing before you wear out your clutch disc. And because that's an entirely preventable condition, we call that clutch murder in the second degree.
TOM: The problem is, if either the disc OR the bearing fails, you then have to replace the whole clutch. To reach either of those parts, you have to remove the entire transmission. And once you've paid for all that labor, you'd be crazy to do half the clutch. On most cars these days, a clutch job is at least a thousand bucks.
RAY: Now, you can take your chances that the throw-out bearing will last longer than the disc, even though you're using it more than you need to, but why risk it?
TOM: So, your friend is absolutely right. The best way to preserve the throw-out bearing is to keep your foot off the clutch pedal, except when you're actively shifting gears (or starting the engine). That way, you'll have the best chance to avoid any clutch-slaughter charges.