mech. told me i need to replace it. ruber seal was trash
how to take off and replace harmonic balancer on 1996 Ford F-150
You will need to remove the belts, and possibly the fan shroud to get enough room to work. Remove the center bolt and install the harmonic balance removel tool. If you don't have one you can borrow one, from auto parts store like Advance, AutoZone, O'Reilly. tighten the center bolt on the tool until the balancer is removed then install new balancer in reverse manner.