I removed the crank pulley on my Corolla to change the timing belt using a diyer method which might apply in your case. To hold it still while I removed the crank bolt, I noticed there were two small holes 180 degrees apart on the face of the pulley. I made myself a sturdy wooden stick using plywood with two wood screws through it, that matched the spacing of the holes. Then I wedged that stick against the ground in an orientation to prevent the pulley from rotating. Crank bolt removed easy-peasy with a socket & breaker bar. There’s a tool called a “pin tool” you can buy that does that same thing. But my wooden stick home-made method worked fine for me.
One thing to be careful about, when pulling the pulley from the crankshaft using a puller, first install the bolt back in-- but not tight – then use the head of the bolt to push on with the center of the puller. What you have to be careful about, remember to monitor the pulley while doing this, so that it doesn’t meet up with the head of the bolt. If that happens and you continue to pull on it with the puller something expensive will break.
I’ve seen ideas in magazines where a diy’er – to remove the bolt – will remove the starter motor and wedge something against the flywheel teeth to hold the crankshaft steady also. Seems like that would work, but removing the starter motor is a pretty big job sometimes. (Just noticed this idea already posted above, sorry for the repeat.)
For a quick tutorial on how the harmonic balancer works and ways it can fail, click below.