Bleeding the Clutch Slave Cylinder

[Excaliber]

Often, especially when bleeding a new and totally empty hydraulic system, I remove the bleeder valve entirely. The master cylinder usually does not have a bleeder valve, you open one of the hydraulic lines to bleed it. If it's brand new and was previously dry (no fluid) AND I forgot to "bench bleed it" (or you don't know how to do that) then I remove the line entirely.

With the MASTER (always start here first) hydraulic pressure port (the line was removed) now completely open you have a couple of choices. You can use the fill it up and go have a beer method, (mostly doesn't work for the Master, often works well for the slave though) or you place your FINGER tightly over the exposed hole and use your finger for a bleeder valve. So the wifey is pumping on the pedal and eventually you begin to "feel" a little pulse, or some pressure. Have your assisstant hold the pedal down while you ever so gently loosen your finger hold enough for some pressure/fluid to come dribbling and later squirting out the hole. CRITICAL next step: Hold your finger tightly back over the hole (like you have closed the bleeder valve) while your assistant releases the pedal pressure. Now HOLD for a few seconds or longer with the pedal pressure released to give the brake fluid TIME to be drawn into the empty cavities and areas internal to the master cylinder. Repeat until your are getting so much pressure it is impossible to stop the fluid from squirting out with just your finger. Put the line back in the Master, it is "ball park bled" and internal cavities and voids are filled with fluid. You are now ready to focus on the slave (clutch, brake, whatever). Same thing, remove the bleeder, cover the hole with your finger and YOUR finger becomes the bleeder valve. When you can't hold the pressure anymore, your ready to install the bleeder valve. Or, go have a beer and let it bleed first, sometimes that doesn't work though, depending of various systems. Almost always works great (have a beer method) on clutch slaves though! Do the clutch master if it's new using the finger method first.

If this bleeding procedure takes a few hours, your doing it wrong, period. Most likely it's because you have SO MUCH air you can't get started with a good bleed. Hence, the "remove the line or bleeder valve entirely and use your finger method" to get in the ball park so you CAN bleed the system!

I never was a big fan of power bleeders using air pressure or whatever, just not my cup of tea. I prefer to hire a neighbor kid, if that's what it takes (give him $5) and let him pump away at the pedal. Unless your going to be doing this for hours, and if thats the case, "your doing it wrong".

You MUST remove the line or the bleeder valve entirely if your going to use your finger. Putting your finger OVER the end of the bleeder valve will not seal the port. It will suck air back in and you will be there "for hours" trying to figure out why this isn't working. Using a plastic line placed over the bleeder valve and the other end of the line in a can of fluid is also a pretty screwed up method. These "self bleeding kits", as they are often called and seen on late nate TV informercials are generally a crock and your throwing away your money. As often as it DOES work (conditions have to be PERFECT, they seldom are) it DOESNT work and again your there for hours trying to figure out how come you can't get the air out and the fluid in!