I guess forgot to do it sooner. Very overdue after 11 years. The fluid was unspeakably dirty, but brakes worked fine. I cleaned the reservoir as much as I could. I never knew fluid can turn to mud. Replaced with fresh fluid and used my spunky new vacuum bleeder. The bleeder screws (brass) were tiny (I didn't have small wrench enough, 7mm was too big) and I had hard time putting universal wrench and hose on them at the same time. I thought it was a bit unusual the screws were at the bottom of calipers too. I managed to get the fluid relatively clean (but never totally clean) at the bleeding screws, but it was going very slow. I replaced the wheels and did brake test and nothing. I guess the bleeding screws should not be at the bottoms after all. Looks like I have a project for next weekend too. Now, a question. Are bleeding screws interchangeable? I'm tempted to put some bigger ones in.