What size is the torque wrench that is needed to remove the lock bolt on the bottom of the main shaft

 

Are you referring to the harmonic balancer? If so, that bolt size would be a 19mm.

 

Not 100% accurate, depends on the car. I know all my 5th gen civics it's a 17mm. I'm talking bolt head aka socket size needed for removal.

 

there is not a correct size because a torque wrench is not a breaker bar and should not be used for removing bolts. not saying i haven't done it... just that it's not good for a torque wrench.

I have broken cheap 1/2" drive breaker bars before trying to remove the crankshaft bolt. so a decent quality breaker bar with a 24" handle is what I use most often. penetrating oil is a must