After spending several years in technical support at a company that sells manual transmissions, I have spoken to many customers who have made clutch installation errors that have cost them a great deal of time, money and frustration. These tips are based on my experience of what a beginner often overlooks when installing a new clutch. This article is NOT a substitute for a good auto repair manual specific to the vehicle you are working on! If any of these tips contradict the information in your service manual, follow the service manual instead.
Tip #1: Lubricate in all the right places (and not in the wrong places!) – Apply a thin coat of grease to the input shaft guide tip and to the collar where the throwout bearing slides. Wipe a VERY light coating of oil on the input shaft splines to prevent rusting. Be careful NOT to get grease on the flywheel, clutch disc or pressure plate.
Tip #2: Get the flywheel repainted no matter how good it looks. It’s only a few bucks and the risk of having to remove the gearbox again because of a rattling clutch isn’t worth the money saved.
Tip #3: Replace the pilot bearing or bushing. Unless you have a dedicated pilot bearing puller tool, some service manuals instruct you to remove the old bearing by filling the cavity behind the bearing with grease and driving the old out with a wooden dowel or an old input shaft. I’ve found that instead of grease you can use play dough, silly putty, or even some stale bread with equal or better results and a lot less mess!
Tip #4: Don’t force anything! If the gear does not slide all the way to the back of the bellhousing, do not pull the gear all the way to the bellhousing by tightening the gear bolts to the bellhousing. I can’t tell you how many broken mounting lugs and damaged pilot bearings I’ve seen! If the gearbox does not slide completely into the bellhousing, the clutch disc is misaligned or the input shaft will not go into the pilot bearing because the gearbox is skewed. Try this: Install or reinstall the clutch linkage, and then have a helper lightly depress the clutch pedal while you wiggle the transmission to align it. When the clutch disc is released it will move allowing you to align the gearbox with the pilot bearing. I once struggled with a gearbox for an hour before it occurred to me, and then it took about five seconds when I had a helper’s step on the clutch pedal!
Before tackling your first clutch swap, I highly recommend reading a repair manual or factory service manual for the full procedure. Even if you’re a seasoned veteran, it doesn’t hurt to take a look at a service manual when replacing a clutch in a vehicle you’re unfamiliar with.