Removing Front Crank Bolt m103
 

Is putting the car in gear and emergency break on the same as locking the flywheel when removing the front crankshaft bolt(300Nm)? Will I damage anything in the drivetrain? Replacing the front crank seal.

nope

If you do not have the "holding" tool then try to wedge a long pry bar against the teeth of the flywheel while you break the crank bolt loose. You will probably have to use a pipe cheater on the breaker bar to start it turning. When tightening it up I borry the 0-600Nm torque wrench from work which makes achieving 300Nm alot easier.