Brake Fluid for Clutch
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Please don't think I'm being argumentative, but...
As a long time track junkie, roadrace pitcrew dood, and whatnot - I have some strong opinions on hydraulic systems bleeding. The only way to absolutely, positively get that last little bit of air out of the system is through positive pressure bleeding. Vacuum pumps don't do it; the method linked above does not do it.
The crux of the problem is air leakage past the threads on the bleeder valve itself. No matter what you do, air gets sucked back into the hydraulic system past those threads. The final step must always be the classic closed bleeder valve (on whichever slave cylinder is in question), and pumping pressure with the master - be it clutch or brake - cylinder, then opening the bleeder on the slave to get that "blast" of fluid out of it. Closing that slave cylinder bleeder before the brake/clutch lever is released, before there is any chance of drawing air back past its threads, is the only sure way to ensure an air-free hydraulic system.
The vacuum pumps and the like are great for getting you "close". Like when changing all of the fluid in a system. Just be sure to complete the process with the old positive pressure method, and all will be well with the system in question. It only takes a couple of pump/release cycles on out tiny systems, with their relatively short lines.
As a long time track junkie, roadrace pitcrew dood, and whatnot - I have some strong opinions on hydraulic systems bleeding. The only way to absolutely, positively get that last little bit of air out of the system is through positive pressure bleeding. Vacuum pumps don't do it; the method linked above does not do it.
The crux of the problem is air leakage past the threads on the bleeder valve itself. No matter what you do, air gets sucked back into the hydraulic system past those threads. The final step must always be the classic closed bleeder valve (on whichever slave cylinder is in question), and pumping pressure with the master - be it clutch or brake - cylinder, then opening the bleeder on the slave to get that "blast" of fluid out of it. Closing that slave cylinder bleeder before the brake/clutch lever is released, before there is any chance of drawing air back past its threads, is the only sure way to ensure an air-free hydraulic system.
The vacuum pumps and the like are great for getting you "close". Like when changing all of the fluid in a system. Just be sure to complete the process with the old positive pressure method, and all will be well with the system in question. It only takes a couple of pump/release cycles on out tiny systems, with their relatively short lines.
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