Rear Main Seal Tips
 

Had a pretty good oil leak coming from the rear of the engine. It was coming out of the weep hole and the clutch fork boot. Nothing above (I was praying for a CAS leak).

Anyway, just pulled the tranny and, sure enough, rear main seal. This is on a crate engine that has been in service for about 6 months and 7000 miles.

Getting ready to replace with a new Mazda seal (the seal that's there was from the gasket kit that came with the engine -- not sure the brand).

Not the funnest way to spend my time. Anybody have any tips to keep me from having to do this again? Or is it just one of those things?

I very carefully drilled a couple holes on opposite sides of the seal, then screwed a couple screws into these holes and used a screwdriver to pry (or pliers to pull; I don't remember) on these screws. This was the easiest method for me. I tried using those dental hooks and ended up ripping up the seal. I also tried hammering one side of the seal so the other side would pop out, but it didn't work very well (though I've heard of several people having success with this method).

I just wish that leaks here weren't so common. Makes me wonder about my crankcase pressure.

I drilled two self-tapping screws into opposite sides of the seal and then levered them out. Basically, the same as Albert.

I used this guy on mine (as well as my camshaft seals) and it worked very well:
Just watch the video down in the reviews section to see how it works if you've never used one before.

^that seal puller is money. Bought it and seriously can't understand how I pulled seals without it. The drilling small holes thing is a bit nerve wracking, but the puller makes it so simple and almost fun