Toyota Repair: Brake Problem, brake fluid reservoir, rear brake drums

Question
My 1993 Corolla 4AFE engine, is losing it's brake fluid on the fluid reservoir fast. If I put brake fluid up to the full mark today, after 2 or 3 days a warning light pops out (brake problem) and brake fluid reservoir is almost empty. The brake is affected of course. What could be the source of this problem? A leak?

Answer
Yes there is definetely a leak in the hydraulic system, the rear wheel cylinders are the most common source, remove the rear brake drums and inspect them, if no leaks are found there check the front wheel brake calipers and the rubber brake hoses, if no toher leaks can be found inspect the brake master cylinder, look for signs of fluid leakage at the bottom where it connects to the brake booster, it may be necessary to remove the master cylinder to inspect for a leak at the rear of the cylinder.