Quote Originally Posted by FF33rod View Post
Hmmm. I came to a different conclusion about the reservoir but am by no means claiming to be right. My reservoir was not leaking but as you noted, I noted that the cap of the reservoir had a hole while the black "gasket" underneath did not. I also noted that the gasket has some folds in it making it quite flexible. I believe this is all as intended and have noted the following. First, most brake fluid is hygroscopic meaning it absorbs moisture from the air. If it does the properties are altered which is a problem. So, I assume this is why the black gasket has no hole. However, the folds in the gasket make it flexible allowing the space in the reservoir to change according to needs. In fact, I had a leak in one of the rear lines and when checking the reservoir noted that the gasket was sucked in a little so I had to pry it off (with a pop) and top up the fluid. The hole in the very top, of course, is what allows the gasket to do its "thing".

Steve
Thank you Steve for that information. I was looking for a fast fix to the problem and overlooked the fact about the brake fluid being hygroscopic. With that I agree the black gasket should not have a hole in it letting air in or out. I switched my gasket with the radiator overflow container.

So it must be caused from me overfilling the reservoir. It is now down to 1/2 full so that should not be the problem. I am still going to check the front brake pads and rotors for excessive wear. Time will tell.