Replacing the Harmonic Balancer ..

....on a '96 XJ. Thanks to someone's tip about use of breaker bar on the frame, removing coil wire, bumping starter a little. The center bolt spun right out ! And the thing came off ok with Autozone harmonic balancer puller rental. Question I have now is this: what makes the key come off the crankshaft ? And does it absolutely need to be replaced with new harmonic balancer ? And, if using the bolt to pull the new HB back on is not recommended, what's the preferred way to do it ?

Thanks !

Ok, the key looks ok, so I won't replace it. Now, I have the problem of how to get the center bolt torqued up to 80 ft pounds. Any suggestions ?

You don't have to replace the key if it's intact.

I usually just tighten the bolt with an impact gun. If you really want to use a torque wrench, your best bet is to get a prybar up into the teeth of the flywheel (where the starter engages) and hold it while you torque the bolt.

Ok, thanks ! I've done all this without removing the radiator. To get my impact gun in there (it's got two settings, 50 ft pds and 250 ft pds), I'd have to remove the radiator. It's stranded in a shopping mall been there for two days, so I'd like to get it home without dumping fluid all over the asphalt there. I'll need to bring someone with me to hold the flywheel with breaker bar. I don't have a longer bolt to use for the method above, so I'm going to try the socket/hammer trick to gently smack the new harmonic balancer back on the crankshft. If it balks, I'll stop and go to a parts store tomorrow for a longer bolt. Thanks again.

Yeah, longer bolt, big washer, and a nut has worked for me. For retorquing, I get the bolt snug and then reinstall the sepentine belt. Then I jam a thick wadded up rag between the belt and pulley to hold everything while I crank on the torque wrench. Blindly hitting it with an impact gun instead of properly torquing it just seems like a lazy hack.

You did replace the front crank seal while you were in there right?

Probably too late but I use vise grips on the edge of the flywheel to keep it from turning when doing the balancer bolt (or pressure plate or flywheel bolts)