Slight leaks are common on any car and can be real hard to pinpoint because normal vaporized fluids can also condense on the engine and look like leaks.
You should really start a new post rather than piggyback on this one. Only CJ MEDEVAC and I will get automated e-mails directing us back here. No one else will see your problem or have a chance to respond.
Also, you should never add brake fluid to the master cylinder except during service to the system. No conscientious mechanic will ever do that during an oil change and many customers think they got substandard service as a result. It is normal for the fluid level to go down as the disc brake pads wear. That is part of the self-adjusting feature of disc brakes. Later, when the pads are replaced, the pistons have to be pressed back into the calipers to make room for the new thicker pads and that is going to push a lot of fluid back up into the reservoir where it will spill over and make a mess. If the level has dropped a lot you either have a leak that requires immediate attention or it's getting about time for a brake inspection.
For a real slow leak, follow the fluid up to its highest point to try to find the source. If there are no spots on the ground where you park, the leak is so small it may be almost impossible to find. There's two things mechanics can do in that case. One is to add a small bottle of dark purple dye to the fluid that is suspected of leaking. After a sufficient period of time you search with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. That works best for very small leaks. For bigger ones we often use a "smoke machine". That puts out a white non-toxic smoke at two pounds of pressure. You inject that into the oil dipstick tube, vacuum hoses, or anything else that is leaking and watch for where the smoke sneaks out. Two pounds of pressure isn't much so that doesn't work well for leaks in the pressurized part of the oiling system. It works better when the leak is in a non-pressurized area such as valve covers, oil pan, and things like that.
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Saturday, August 4th, 2012 AT 3:08 AM