I release the clutch…and the car doesn’t move

Question:

I am working on a 1995 GMC Sonoma. It has a new clutch, throwout bearing and pressure plate. Here’s the problem: I’ll drive it for a while then come to a stop and pull it into first gear. When I release the clutch the engine revs but the car won’t move and acts like it is in neutral.

The clutch reservoir is full of hightemp brake fluid, but the problem is still there. One mechanic said to check for an exhaust leak near the line from the reservoir that could be causing the fluid to heat up and become ineffective. Any advice would be welcomed.

Answer:

It would be a good idea to grab a flashlight and check for interference with a hot exhaust, but the problem is most likely going to be air or even moisture in the hydraulic clutch system itself. Check the system for leaks, and if you do not find any, bench test your clutch hydraulic cylinder to make sure it is in good order and then purge and bleed the clutch hydraulic system according to the instructions in your shop manual. It normally involves opening a check valve in the line and then depressing the clutch slowly until the air is expelled. Be sure to top up the hydraulic cylinder before going for a test drive.