This guide is for the installation of a brand new main seal on the flywheel side of the engine for any 88-91 CRX. If you see evidence of oil leaking out from under the transmission/engine mating surface, this is a likely culprit.
Driver tool or PVC pipe (same diameter as seal)
2 sheet metal screws
Brand new seal (from honda)
Big flathead screwdriver or small pry bar
Removal of old Seal
The document assumes that you have already removed the transmission, clutch, and flywheel from the vehicle. If you have not, please review the other "How to's" on those subjects first.
First, the take your sheet metal screws and screw each into opposite sides of the old main seal. The main seal is only about 3/8 of an inch deep, so don't screw them in too far.
Once you the screws are secure in place, you need to pry on them with a big screw driver or small pry bar. Pry against the end of the crank shaft...not the aluminum block. The crank shaft is hardened steel. The block is soft aluminum and will scratch and gouge easily. Alternate prying between both sheet metal screws. The seal will eventually pop right out. Discard the old seal.
Installation of new seal
Once the old seal is out, clean up the seal surface on the block. It should be clean, dry, and free of any grease or oil.
If you do not have a special driver tool to hammer in the new seal, you will need to go to your local hardware store with the new seal and find a piece of PVC pipe that has the same outer diameter as the new seal. Use this piece of pipe to hammer in the new seal. My PVC pipe was actually a pipe end cap, so I could hammer directly on the end of it. If yours is an open ended pipe, you may need to use a small block of wood over the end of it to evenly distribute each blow of the hammer. Be sure to only exert force on the outside edge of the seal. The inner area is delicate and surrounded by a thin precision spring. Hammer the seal into the block until it bottoms out in the block. Make sure it is evenly seated into the block all the way around the seal.
Clean the spilt oil from the area below the main seal. If you see oil again in this area in the future, you will be able to diagnose the new problem. In addition, the less oil that is sitting around in the clutch/flywheel compartment, the less chance that you will contaminate your clutch with oil.