It’s a certainty. If you drive your Corvette, parts will wear out. If your car is moving, the tires are wearing. When you’re stopping, the brake pads are wearing. And when you’re starting off from a stop, the clutch is wearing.
Fortunately, taking off from a stop in First gear is pretty much the only time the clutch wears. In fact, the clutch can last well over 200,000 miles in a car that’s primarily driven on the highway. Clutches wear faster in city driving and much faster in very hilly cities like San Francisco.
It’s fortunate that your clutch will outlive tires and brake pads because the labor cost for replacing the clutch is higher. For many cars, the labor cost is a small fortune. However, for early Corvettes the task is not as bad, at around five hours with parts cleaning and inspection.
Clutch replacement is a relatively straightforward task when using good parts and paying attention to the details. It’s wise to do a pre-inspection to determine if other parts are needed, and to determine if rust will make header pipe removal difficult.
Although this job can been done if the car is jacked up sufficiently, it was made much easier when the good folks at Vansteel let us use their lift. In either case, make sure that the car is securely supported on blocks, stands or a lift. Don’t overlook this safety priority because you’ll be tugging on the exhaust and pushing on the transmission.
Let’s start with clutch removal on a C3. It’s the same process on a C2 and nearly identical on earlier models. Next time around we will go over clutch options, important inspections and assembly details. In both parts, we’ve sprinkled in time-saving tips not seen in the factory manuals.
01. Remove the distributor cap and rotor as a precaution. If the engine is lowered, either of these could crack if they hit the firewall. Also, unscrew and remove the tachometer cable from the distributor.
02. Unscrew the shifter ball and remove the T-handle and spring. Have a cloth handy for the T-handle because it can be dirty or greasy. The factory service manual says to remove the console plate and seal assembly (shifter boot) but I’ve never found that necessary.
03. The factory service manual also says to disconnect the battery. I see no reason to do this, but if you’re very cautious the battery can easily be disabled from underneath by unbolting the ground cable where it attaches to the frame.
04. Remove both exhaust pipe clamps at the transmission mount. If you inspected them earlier and found their threads are very rusty, it’s good to have replacements on hand. I prefer the stronger 3/8-inch diameter clamps over the stock 5/16.
05. For leverage, grasp the front of the muffler and the tailpipe where it bends near the differential. Twist the pipe up and down to break the pipe loose from the header pipe. Be careful to not smash your fingers between the pipe and the strut rod bracket!
06. Remove the three nuts connecting the header pipe flange to the exhaust manifold on the driver side. If these nuts do not break free easily be very careful not to break the studs. If the nuts are rust seized, go to a muffler shop to have them removed. Long brass nuts used with lock washers are my favorite for the manifold studs.
07. Wiggle the driver-side header pipe down from the manifold studs and then forward and out. The factory service manual says to remove the passenger side header pipe, but it’s not normally necessary. Just loosen its three manifold nuts to enable the engine to be lowered slightly.
08. Remove the two bolts attaching the transmission mount to the frame bracket and the two bolts attaching the rubber mount to the transmission. Note for later that the lower bolts have large flat washers and the upper bolts do not.
09. Place a wooden block under the rear of the oil pan before gently jacking it up just enough to remove the transmission mount. It doesn’t take much pressure to jack the rear of the engine up because the motor mounts carry most of the weight.
10. Remove the driveshaft U-joint bolts and the two bolts holding the shifter bracket to the rear of the crossmember. Unscrew the speedometer cable and withdraw it from the transmission.
11. Turn a rear wheel until the cups are horizontal when separating the driveshaft U-joint from the transmission yoke. Be extra cautious because it’s no fun to drop a cup on the floor and have to search for and clean all the needle bearings.
12. Remove the transmission mount and the exhaust pipe bracket. Remove the six 3/8-16 bolts from the transmission mounting bracket. This photo helps show what these parts look like; it’s s a little cramped and confusing when they are in place.
13. Unbolt the three shift levers from the transmission. Also unbolt the reverse light switch, and the reverse lockout cable and TCS switch, if so equipped. Be gentle with the wires, their insulation is often brittle from years of heat and oil.
14. The most tedious portion of the process is removing the two shifter mounting bolts. The upper bolt can only be turned 1/12 of a turn at a time with a wrench. I’ve found it best to unbolt the upper bolt first and then move the levers to get a socket onto the lower bolt.
15. After removing the shifter and then its support bracket, remove the four bolts that hold the transmission to the bellhousing. A 3/4-inch flex socket can help with the upper bolts. Slide the transmission rearward out from the bellhousing, rotate it a little and lower it from the car. Lower the engine a little if needed to get the transmission to clear the bellhousing.
16. Remove the cotter pin and the pin to disconnect the clutch rod from the fork. It’s worthwhile to remove the other end of this rod too. Clean, inspect and lubricate the wear surfaces. Note the springs at both ends of the rod. Often they are missing.
17. Look at how the tabs of the bellhousing cover are inserted in front of the lip of the oil pan. It’s common for these tabs to be bent, broken or out of place. Remove the four small bolts that attach the cover to the bellhousing.
18. Look to see if a ground wire or wire loom bracket is attached by bellhousing bolts near the starter. It’s common for people to forget to reconnect the ground wire. Then later, they’ll find that the heater blower motor or the windshield wipers do not work.
19. Remove the six bolts that attach the bellhousing to the engine. If there’s a foam insulator, carefully remove it to access the upper bolts. A 9/16 flex socket is useful to remove the upper bolts after they are broken loose. Slide the throwout bearing off the clutch fork and then remove the bellhousing. It may take a little gentle tapping, prying and wiggling to get it off the engine’s alignment studs.
20. Insert the alignment tool through the clutch disc. Loosen the six pressure plate bolts about a turn at a time until the pressure is released. Remove the bolts and the pressure plate. Be aware the clutch disc may try to fall out at the same time. Also, be careful of the fingers on the old pressure plate. If they’re excessively worn, they will be sharp.
22. With the clutch disc and pressure plate removed, the wear surface of the flywheel is exposed. It’s time to closely inspect the flywheel, and clean and inspect the other parts before installation of the new clutch assembly. We will take care of that next time.