When I first got the car I bled the brakes and topped off the reservoir. The car had other problems and I had to park it for about 6 months before finding time/money to work on it. When I went to work on it all the fluid in the brake reservoir was gone. There were no visible leaks and no spots on the floor. Filled and bled.

After getting it on the road for a few months I lost almost all of the fluid from the reservoir again. I followed the lines by sight and feel and couldn't discover a leak. Same for all the calipers. No spots on the garage floor unless it is mixing with my oil leaks. I bled the brakes and topped it off. Fluid level didn't drop for a month then suddenly down about an inch on the reservoir. No idea where this much fluid is going.

I also have a brake shudder. Some times slight, some times a little violent and other times not at all. I was thinking rotors but shouldn't I feel it all the time? It can go a whole week with no shudder or won't go a day. One time shudder next time braking, not at all. Could it be related to the mysterious fluid leak?

 

yeah, it sounds like you sometimes have a leak and sometimes don't which correlates with your caliper. It could be any odd thing, maybe a pitted piston that sometimes catchs the seal in a certain way and sometimes doesn't.

My car first leaked at the hoses from the reservoir, so i replaced them. The increased pressure made my back calipers leak, rebuilt those. Then my master cylinder leaked. It just happens after time

 

Your fluid in the brake buster.