Put a smear of sealant on the case splitline only, did I say just a smear, lube the inside of the new seal and press it in. There isn't really a trick but if it's tight use a block of wood to gently tap it in evenly. The recess is probably 12mm deep and the new seal 10mm so knock it in flush with the surface. I know you are using a new flywheel but make sure the sealing area is smooth. Have you decided to leave the bottom end alone?
I’ve got a (very) large repair washer, the same diameter as the seal with a hole the same size as the thread on the gland nut. I just position the seal in place with a little oil on the outside then place the washer over it and put the gland nut in and tighten it, pushing the seal squarely in.
It’s the big bolt that holds the flywheel on (it’s a type 1 engine I’ve got- not sure if the type 4 has the same set up) anyway the big washer just keeps the seal nice and square as it pushes it home, tightening the gland nut to push it in.
That washer is a part of an EMPI Type 1 seal fixing kit.. that never works because the crankshaft dowels of a T1 need removing to get it to go in far enough. Then all the T1 owner needs to do is calmly do up the gland nut onto the washer on top of the seal and the seal gets pushed in..
