How to Bleed the Clutch Hydraulics
My C5 recently was exhibiting hydraulic clutch problems. It was not releasing all the way causing hard shifting and grinding gears! I checked the fluid in the master cylinder and it was at the right level but it was dirty! It was dark gray and pieces of something were floating in it. After posting a question to the CorvetteForum, several other C5 owners were exhibiting the same problems. Is the seal on the cap deteriorating? Is heat causing this? Who knows? This problem seems to happen in C5\'s that are 4 years old or older and the symptoms start to appear when cold weather comes around. Well, after changing the fluid in the reservoir several times using a turkey baster, I got the clutch to operate sporadically good, but it was still having problems. After consulting the Service Manual, I decided to bleed the clutch, which resulted in a 100% improvement. Now, my C5 shifts like it is brand new! Instructions with detailed step by step pictures are at http://97vette.com/howto/clutchbleed/index.html First, clean all the dirt and debris, if any, from the clutch master cylinder cap to ensure that no foreign substances will enter the hydraulic system. Remove the clutch master cylinder reservoir cap with diaphragm. Fill the reservoir with clutch hydraulic fluid (DOT 3 brake fluid or GM P/N 12345347). Raise and support the C5. Remove the intermediate exhaust pipe. To do this, you must first disconnect the O2 sensor cables. GM recommends that you disconnect the batter before performing any electrical connections/disconnections. I left the battery hooked up and I was fine. The connectors are located above the exhaust pipes just to the rear of where they connect to the exhaust manifolds. Remove the blue retaining pin. And, disconnect the wiring harness. Then, remove the retaining clips. Now, remove the 3 nuts which hold the exhaust pipe flange to the exhaust manifold. There are 3 nuts per exhaust pipe that need to be removed with a 15mm socket. I suggest leaving one nut on each pipe, loosely, so that you can disconnect the rest of the exhaust system first. Once all the other bolts have been removed, and the rear of the exhaust lays on the floor, you can easily undo the 2 loose nuts and lower the rest of the exhaust. Then remove the exhaust bolts at the other end of the exhaust pipes. There are 2 bolts per exhaust pipe that need to be removed with a 15mm socket. Then, locate the forward exhaust hanger, just behind the clutch bellhousing. There are 2 15mm bolts that need to be removed. Next, remove the 2 rear exhaust hanger bolts. These require a 13mm socket. Undo the 2 loose nuts from the front of the exhaust assembly and lay the exhaust on the floor. Slide the exhaust assembly out from under the C5 and put it out of the way. Next, locate the 36 bolts that hold the Driveline Tunnel Closeout Panel in place. This is just above the exhaust assembly you just removed. These bolts require a 5/16\" socket. Remove all but the rearmost and forward most bolts. Then, remove the rear, and support with a leg or a 2x4 while removing the front. This panel is not heavy but it is awkward. Place the panel aside. This exposes the torque tube. Face the front of the vehicle and reach your hand up around the driver\'s side of the torque tube until you feel the bleeder bolt. Put a 7/16\" wrench on the bleeder bolt and have an assistant depress and hold the clutch pedal. Loosen the bleeder and retighten. Fluid will shoot inside the torque tube tunnel and run down your arm, as well as inside the bellhousing. Tighten the bolt and have your assistant release the clutch pedal. I found that after I bled the system, my assistant had to pull the clutch pedal off the floor. But, it operated fine after that. GM recommends doing this 7 to 10 times until you have bled any air or bad fluid from the system. Every 3 to 4 bleeds, add more fluid to the reservoir in order to prevent removing so much fluid that you draw air into the system. When you have completed the bleeding procedure, wipe any and all excess fluid from underneath the C5. This stuff is flammable and you don\'t want to catch your C5 on fire. Then, reverse these instructions to reinstall the Driveline Tunnel Closeout Panel and the Exhaust Assembly. Then lower your C5 and test the results.