Got 5 gal of 100LL in a fuel container. Calibrated a dip stick for container. It actually works out to be 1 gal for every 2 1/4 inches. Leveled airplane left and righrt. Fore-aft was about 1.5 fdeg nose up. Closed service valves. Poured 5 gal into right tank. Disconected line from tank drain inside cabin. Drained fuel back out till it would not drain anymore. Measured amount drained at 4.5 gal. This determined that there was .5 gal unusable fuel in right tank. Did the same thing for left tank. .4 gal of unusable fuel in left tank. Total unusable fuel is .9 gal.
Poured remaining fuel equally into each tank. Open tank service valves. Fuel drained substantially equally into sump tank. Low level warning went out. No apparent leaks