Re: Harmonic balancer
No special tool required... a second 10mm spanner or a big flatblade screwdriver as a brace to stop the pulley turning is all that is needed.
Usually its not the pulley that is warped, but the bearing in the water pump goes creating freeplay. There is very little room for movement inside the pump where the impeller sits and it could be hitting the metal plate inside which creates the vortex for water flow.
88 EA Falcon S
RIP my ol' esky.. many years of good service