1985 190e rear pinion seal leak

[etch60]

good day guys.... on me sons 1985 190e merc i raised rear of car and replaced rear brake pads and whilst there decided to check the rear diff oil level as we've had the car only a week ..... so i busted me chops to undo the 14mm plug out and stick me little finger in and absolutely no oil in there to be felt ... so i put in castrol diff oil of about 600 to 750 ml in no problem.. whilst i had the car still up i decided to start and run it to bed the pads in ....i had a look after i stopped motor and there was a drop of oil on the pinion flange where it meets the driveshaft .. and and above that on the body i could see and feel thats where during its life where it has leaked from and on to .... so question is would it be wise for a home mechanic as myself to change the pinion seal or will it take special tools ,methods etc? i have done a couple of other brand cars and found them straight forward to do except the undoing of the large nut inside the pinion gear is the merc 190e very hard to do and a difficult proceedure ( ""any boooby traps to look out for "")? any help appreciated