Clutch Situation: C5 Twin-Disc Clutch Install

The original clutch is pretty well spent, showing considerable wear onthe pressure plate that is supposed to grip firmly against the flywheel.

Next, John loosens and removes the six engine flywheel bolts...

...and removes the old flywheel from the engine crankshaft flange.

Before going further, John decides to replace the clutch pilot bearing.Looking upwards through the bottom of the flywheel inspection access, wewatch John slowly pull the old pilot bearing out from the crankshaftflange. His pilot bearing puller works a lot like a traditional winecorkscrew.

The used pilot bearing has been successfully exhumed from the crankshaftflange. The pilot bearing is only a $20 item and ought to be replacedwhile this much of the car is torn apart. Removing it ensures that thebearing must be replaced as its guts are destroyed in the process.

Looking directly at the back of the engine block through thebellhousing, we see that John has already installed the new pilotbearing in the center of the crankshaft flange. It is tapped firmly intoplace using a hammer against a pilot bearing installer, which resemblesa large punch.

The new Exedy clutch and flywheel is shipped as an intact unit, but Johnmust unbolt the clutch assembly from the flywheel in order to bolt theflywheel to the engine. As he removes the clutch housing from theflywheel, we see one of the carbon metal clutch plates sitting on theflywheel, and get a peek at the other clutch plate inside the housing,behind the center plate that separates the two discs.

Ignoring the obvious heavy wear and glazing on the stock flywheel(right), the difference in design between the machined Exedy chrome-molyflywheel and the stock one is significant. Although their overalldiameters are the same, the heavy-duty Exedy clutch has a much smallercontact area to the flywheel. The Exedy piece also weighs significantlyless than the OE.

To secure the new flywheel to the engine crankshaft flange, John appliesthreadlock to the bolts, then tightens the bolts in three stages and ina triangular pattern, like attaching lug nuts to a wheel. In the firstround, he torques the bolts all to 15 lb-ft, then to 37 lb-ft, andfinally to 74 lb-ft.

Exedy supplies a plastic clutch alignment arbor to align the clutchplates to the pilot bearing, but since the West Coast Corvettes shop iswell equipped with tools and parts, John uses a spare propeller shaftend to align the clutch plates instead. This fits much tighter to allowfar less tolerance, which will make attaching the real propeller shaftmuch less difficult later on.

With the clutch plates properly aligned to the pilot bearing, Johninstalls the visible clutch cover bolts finger-tight to the flywheel,then rotates the flywheel all the way around so he can finger-tightenall of the cover bolts.

Finally, John rotates the flywheel around and tightens the clutch coverbolts evenly, like the flywheel bolts before, in a triangular sequenceover three increments, with the fourth and final round to 47 lb-ft. Theclutch itself is now completely installed.