The Stovebolt Site Forums The Shop Area Engine Shop Front Engine Oil Leak 235

This is a somewhat tedious job, not meant for the “Faint of Heart”, but with guidance, doable by most that possess a bit of mechanical aptitude.

You’ll need to pull the harmonic balancer to replace the seal. The balancer has threaded holes to bolt a puller to. You can rent one from most FLAPS. Don’t use a three jaw puller as it may damage the rubber or rivets in the harmonic balancer.

Once the balancer is removed you have access to the seal. A bit tricky, but you can get the old seal out, without pulling the timing cover. Don’t attempt to pull the cover, as access to the two lower bolts are from inside the crankcase. I used a small three jaw puller with the jaws inverted. I’m sure there are other methods, that other on this forum would love to share.

Once removed, inspect the area on the harmonic balancer for wear. If worn, you can buy a stainless steel sleeve to go over the worn area to give your new seal a nice area to ride on. Mine needed the speedy sleeve so I provided a picture of what it looks like installed.

Assembly is a bit more tricky but certainly doable! To tap the new seal in place, I use a large socket that contacts the outside edge of the seal and has clearance inside for the crank shaft. A little smear of #2 Permatex or suitable Locktite on the OD of the seal helps.

Next is to replace the balancer. A subject of debate as to how to do it, has been raging for years on this forum. I installed this balancer by hammering it on the same way the GM factory trained mechanics did it for years. You will need to drive hardwood wedges between the flywheel and the back of the bell housing, to protect the thrust bearing on the crank. You’ll also need to use something like a block of wood (on the end grain), to protect the balancer from hammer marks. My balancer has the ears for a hand crank, so I fabricated a installation tool from a few black iron fitting, so I had clearance for the ears.

Others have threaded the snout on the crank shaft, so you can use a balancer installation tool, definitely a much gentler method with the added security of a bolted on balancer.

Good Luck!