diesel rabbit oil seal leak confirmation and seal replacement

I believe that I may have a leaking main oil seal ('front' or passenger
side). Before I charge into changing the seal I would feel happier if I
can make sure that the leak is not from somewhere else. I plan to clean
the outside of the engine as much as is practical - any tips here?

Oil seal change concerns: I have looked in my Bentley manual. Some
things that bother me are special tools that are called for (one tool to
remove the old seal and another tool to press in the new seal). The
other possible problem relates to unbolting the (small) timing belt
sprocket from the crankshaft - the tightening torque specified is 110
ft-lbs(!).

To loosen the crankshaft bolt from a Toyota 22RE (after consulting
published tips) I braced a socket wrench which held the crankshaft bolt
and (after disabling the spark) hit the starter motor. PING! and it
broke loose (whew).

I get the idea that there isn't a woodruff key to align the sprocket
with respect to the crankshaft - instructions for replacing the timing
belt include bracing the camshaft, the injector pump, and the crank (jam
a large screwdriver into the teeth of the flywheel?!) I THINK THAT I HAD
BETTER NOT DO THIS TO IMMOBILIZE THE CRANK WHILE REEFING ON THE
CRANKSHAFT BOLT.

Thanks for any advice, Rob in Calgary