As of late I have to add brake fluid just about every 4-5 days. I just recently had my rear brakes completely replaced, but even after that I'm still losing fluid faster than I should. I think the problem is with the reservoir since the cap doesn't won't tighten onto it. The cap will reach some point of maximum tightness and then if turned again it seems to slip off the reservoir. The only other thing I think it could be is a hole in the brake line. I drive a 2003 Kia Spectra. If someone could tell me how to replace a brake fluid reservoir and if it's something I could do myself, since money is tight right now. Also any other ideas on what the problem could be would be appreciated, since you guys know way more about this than I do. Any help is appreciated.