84 R80G/S crank seal

Advice req for installing the rear crankshaft oil seal.
I have the mandrel for inserting the seal,part No 111882 and a spacer which locates on to the mandrel,part No 111881.This inserts the seal deeper into the housing.
What I need to know is do I use this spacer on the mandrel or not for my machine.As I believe the depth the seal is set at is quite critical.
Hope somebody can help me with this one.

You`ll probably get an answer here,but this would have better in the Airheads Forum

Insert the same depth as the seal thats already in place