Here's a hint when replacing a slave cylinder, or even a wheeel cylinder or caliper... if you fill the master to the top and place a suitable piece of plastic over the reservoir and then screw on the cap, you'll loose very, very little fluid and save a mess, and have less air to purge. I've even done the above, and simply opened the bleeder on the replaced part, pull the plastic off, and let it flow. No bleeding required, sometimes. Peter C.