I recently replaced the speedometer/odometer in my '59 Olds with a rebuilt unit. I transferred the fuel guage and printed circuit from the old cluster to the new one. While I was transferring the fuel guage over, I watched the needle move slowly from half full to empty. Now that everything is reinstalled, the needle remains on empty, even though I filled the tank. The shop manual calls for using a "Tester 11-13", which I do not have. I know the problem is not in the tank, as the guage worked prior to moving it over to the new unit. I did not damage it or the circuit board, as I was very careful during the process. I guess it's more important to have a working speedo than a gas guage, but I would prefer to have both! Any suggestions? Thanks!