The throwout bearing is, in my experience, that "one damned little part" that costs about $20 to make but well over a grand to replace. It's a fairly small bearing about the size of a hockey puck, and it takes pressure exerted by the clutch fork (which is, in turn, under pressure from your left foot) and transfers it to the clutch pressure assembly, which will then move its metal fingers away from the clutch disc. The reason for this bearing is that the clutch pressure plate is often spinning and, ideally, the clutch fork isn't.
The reason this part can cost so much to replace is that it sits around a shaft that the transmission has rather crudely crammed into a hole in the clutch pressure plate, which is bolted to the engine's flywheel. Getting to this accursed little failure-prone part requires separating the transmission from the engine and, in the case of my BMW, removing the entire drive shaft, power steering pump, dashboard, and license plate lamps1.
At this point, it should be clear that the throwout bearing in my BMW is in fact periously close to complete failure. Bummer.
The way I figured this out was the grating felt through the clutch pedal got dramatically worse and there's now a rather awful-sounding whirring coming from the transmission's bell housing any time the clutch is depressed. The fact that I could feel any sort of grating in the clutch pedal has been a long-standing indicator that this throwout bearing would eventually fail—but there's been no compelling reason to replace it up until now.
So, my options here are twofold.
- Suck it up and eat the over-thousand-dollar cost for someone else to tear this whole mess apart. While they're in there, they should probably replace the driveshaft flex disc (another $20 part with multi-hour removal implications) and the transmission mounts ($100). And possibly the knock sensors, while you're down there. And dammit, I probably should just replace the clutch now, too. (Clearly, you can see where this is going).
- Rent an engine hoist to keep everything under the hood from falling out, and then pull the transmission myself and replace just the throwout bearing, the driveshaft flex disc, and the transmission mounts. Oh, and the knock sensors. But not the clutch, because I don't want to have to pull the flywheel and put it all back together again.
So, recommendations? Has anyone here replaced the clutch on a longitudinally-mounted engine? Am I crazy for wanting to pull the transmission but not wanting to take the flywheel out?
1 Not really.
I did it on a ford falcon, and (less related) a bettle.
I say do it yourself - and sence you'll be saving all that money by doing it yourself, get an uprated clutch and lightened flywheel.
If the knock sensors dont look worn, dont replace them.
So, it wasn't too hard on the Falcon? Did you have to pull the entire transmission to do that one?
And I'm not sure how much the Beetle counts—you can just pull the whole engine straight off for that one. Easy peasey!
I'm not sure that I need to replace the clutch, and I'm really fairly sure I don't need an upgraded one. And I've thought about a lightened flywheel before...but I spend so much time in traffic that it seems like a bad idea. Any thoughts?
Also, the knock sensors aren't checked visually—you know they go bad when they start flagging the Check Engine lamp every now and then. And since they've been doing that once every few months, I know they're due for replacement :)
--Dan
You know what? I can get an OEM clutch kit for $200. So, maybe I will just do the whole clutch at once.
I would have thought it was going to be waaay more. Even the OEM clutch kit for my Talon cost more than this.
--Dan
yeah, the falcon was easy - easier than the bug actually but only because the bug engine is heavier than the falcon tanny. I just propped the back end of the falcons engine up with an old log we had lieing around in the back yard and viola - engine supported!
Dammitalltohell—I'm not sure why I can't remember doing shit like that. That's exactly the way I used to prop the engine up in my Talon when I had to pull the upper motor mount off. Either jack the engine up, or put the engine on a pile of crap and lower the chassis a bit.
Good show, old chap. I think I've got this one licked.
alternatively you could build a complicated truss of 2x4's to support the engine sans tranny. add some plastic fittings and some of those knobs that do nothing for good measure.
2x4s? Nah—I've got a pile of PVC tubes and a whole pocket full of zip ties ready to support an engine.