When only replacing the front crankshaft seal

Fig 1: Identifying Seal Installation Using Tool 9995455

Courtesy of VOLVO CARS OF NORTH AMERICA.

Remove the old seal. Use a groove-cut chisel or tool 9995919
Clean the mating surface
Grease and install a new seal.
Use tool 9995455
Press in the seal using a drift and the crankshaft center nut as illustrated.
NOTE:
Ensure that the crankshaft does not rotate when pressing in the crankshaft seal.