Here is how to prime the clutch. The whole process should take under 20 minutes. This is how the system works - The clutch operates using brake fluid. It draws off the brake fluid reservoir via a black tube on the side. Fluid flows from the reservoir into the cylinder above the clutch pedal (when there is a negative pressure). Then when the pedal is pushed the pedal cylinder pushes fluid through the tube into the clutch slave cylinder which activates the clutch. The clutch slave cylinder is attached to the tranmission on the front, lower, left side. It is a black plastic cylinder that has the bleed valve. Look under the driver side head light a little inboard. When there is air in the system simply pumping the clutch does not prime the system. It just moves a little fluid back and forth. And pumping until your arm falls off will not do anything.
Step (1) Attach a clear 3-foot tube to the bleed valve. Keep the tube elevated to keep air out. Place other end in a plastic bottle to catch fluid. Note: The clutch slave cylinder is after the bleed valve and therefore difficult to remove air. The method described here will allow you to push fluid into the clutch slave cylinder.
Step (2) Pull the pedal up, open bleed screw, push pedal to the floor, tighten bleed screw. Then very slowly pull clutch pedal up. This allows the fluid to flow into the petal from the brake fluid reservoir. Repeat the process (up, open, floor, close, pull up slowly). You should see a mixture of air and fluid flowing into the tube. Keep repeating (5-10 times) until the fluid flowing in the tube is void of bubbles. Note: Make sure that the brake fluid in the reservoir remains above the clutch passage.
Step (3) With the bleed valve off you should start to feel resistance when you pump the clutch pedal. If the pedal is soft you have air in the clutch slave cylinder (or a leak in the system noted by a brake fluid puddle).
Step (4) Prime the clutch slave cylinder. Make sure the clear 3-foot tube that is attached to the to the bleed valve is still filled with fluid. Empty out the last 4" from the end. Clean the end with a lint free towel and soap and water. (be careful not to get anything into the tube).
Step (5) Blow into the tube (or attach a small pump) to push fluid back into clutch slave cylinder. Try to push at least 2 feet of fluid back into the system. But stop before emptying the tube. Then close the bleed screw. (be very careful not to get any fluid into your mouth)
Step (6) With the bleed valve off pump the clutch pedal. You should feel close to normal resistance at the top of the pedal.
Step (7) Clear any air that you pushed out of the slave cylinder by repeating Step (2) a couple of times (up, open, floor, close, pull up slowly). Stop when you have pushed out more fluid than you blew back in.
Step (8) With the bleed valve off pump the clutch pedal. You should feel normal resistance at the top of the pedal. If not you may need to repeat the process. This works for me the first time.
That is how I did it for about two weeks or so about a 1/2 hour a night, and went through nearly a gallon of DOT 4 and still had a spongy pedal, bubbles in the fluid and even tried pressure bleeding with the pressure tank for the brake reservoir, but still had poor results until I contacted a very nice dealership that put me on the phone with one of the mechanics who gave instructions over the phone, apparently the "secret" instructions. He told me to take a long pole such as a broomstick handle and press the clutch pedal to the floor, brace it, I used the seat with a rag on the end to not damage the leather, and "leave it overnight." I had never heard of this trick, and had exhausted all other options listed above. So I did just that, when I went to check on the clutch the next day, I removed the broom handle, the pedal was still on the floorboard, I reached down and pulled it up, I heard the usual liquid sound of fluid entering the system, but here's what I had, the pedal play was gone, it felt as if it were brand new. I have posted this on another mini site to inform all the back yard mechanics out there of this "secret technique."
11/08/2011 @ 10:29 PM
Replaced my clutch slave cylinder this weekend as it was leaking into the dust boot. Compressed the piston with a bracket before installation but still ended up with air in the system. Followed thors advice last night by bracing the clutch pedal to the floor overnight. This morning it worked like a charm. Thanks for the help!
12/25/2011 @ 11:31 AM
i had to laugh when i read this but it kinda makes sense, just replaced tranny for a getrag on my 05 conv and have about 2 hours invested in bleeding. i will try this trick today and will inform. lol
03/15/2012 @ 8:49 AM
Bleeding it will take two people. The way I do it is this:
Gain access to the bleeder valve and crack the valve open. With the valve open have the person in the car depress the clutch pedal. When the pedal is all the way down close the bleeder, now the person can bring the clutch back up, it may have to be pulled up. Now pump the clutch pedal 5 times, and add fluid to the system. Repeat until the pedal is back to normal.