I'm trying to remove a Gerber shower faucet handle. My shower is the 3 knob
type.

I've removed the screw that holds the knob in place, but it still won't come
off. I have pulled with what I, myself, consider to be a substantial amount
of force, but the knob still won't come off. Should I try to force it off
by pulling with all my might using both hands, or could doing this cause
damage to the valve, etc.?

I notice that when I pull on the knob, there is some movement beyond the
knob, but there is zero evidence that the knob itself is loosening. In
other words, when I pull on the knob, the whole valve assembly ( not sure
the right terminology) seems to pull outward slightly and then stop, but the
knob is not loosening at all. I'm afraid to apply more force as I don't
want to damage anything. I just want the knob itself to come off.

Should I just bite the bullet and try and force it off with all my might
using both hands, or could doing this potentially cause damage to the stem,
the valve, or the bath-tiles etc.?

Would I be better off purchasing a special handle-puller tool to remove the
knob?

Any other suggestions?

Thanks,

J.