What's to prevent oil from leaking from the back side of the hub through the bolt hole?

? the bolt hole on the tip of the nose of the crank? i'm not at home to check the diagrams, but isn't there an o-ring in the assembly and a washer under the bolt in the hole in the nose of the crank? the washer is a big thick washer and the sides are at a slight angle.

Whaaaaaaaaat?

3 fastners hold the fan to the hub.

1 fastner holds the hub to the crank (blind hole)

The hub rides in the front seal.

O ring #4

While the hub on the crank is not an interference fit, it is somewhat tight. You would have to build up crankcase pressure and the oil would have to squeeze between the snout of the crank and the hub to the washer, go under the washer and come out from underneath the bolt head.

With that kind of crankcase pressure, the lips on the front seal would be flappin and pushed outward before it came out from under the bolt head.

this is my opinion only .... others may vary ... but variety is the spice of life and afterall, I don't give a flyin' fuch ...........

Ed, I believe that oil ring #4 is actually the front seal that seals around the hub. But it doesn't do a thing to seal the back side of the hub or the ID of the hub and the bolt hole.

This fire-breathing 2056 does build a good deal of crankcase pressure. I'll come clean though. When I tipped the motor towards the front I kept getting oil leaking from the front hub. It was on the washer. WIpte it off and it would come back the next time I tipped the motor. When I went to check the torque on the hub bolt, it was loose to say the least. But like a Jeep differential yoke, oil could theoretically leak past the back side and through the bolt hole or between the washer and the hub. If the bolt was tight enough in the first place then perhaps not. But I'm going to put a dab of sealer on the washer around the circumference of the hub and the bolt just to be sure.

I pulled this thing to do a transaxle swap, a re-seal and to install head vents. If I put it back in and it leaks I'm not gonna be real happy...

It's a precision taper fit, and damn tight, once the bolt is torqued to a mere 18 ft/lbs. The o-ring behind the hub seals the joint between the crank and the hub, the radial seal between the hub and the case. if your hub was loose, I'd REALLY carefully inspect the surfaces of both the crankshaft and the hub. use a bright light and magnification if necessary. Also look at the key and the keway in the crankshaft. Perfection is a must here, anything less can cause the hub and crank to separate during operation, and that's something you REALLY don't want to happen.

The Cap'n

seal is #13

I'll be damned. Good thing I asked. Thanks!

There is absolutely no trace of an o-ring on this motor. And that would definitely be one of the prime sources of my oil leaks. I'm going to have to source an o-ring locally. Anybody have a size?

Odd size, and size is critical. Remind me in the AM and I'll get you the part number. ANY VW dealer can have it in 2 days. The Cap'n

That'd be great John. Would it be the same as the part number in Pet or could it have been superseded half a dozen times? The PET number is 021-119-125-A-OEM

Pelican lists it right below the fan with the same p/n

18 ft/lbs?

I coulda sworn the factory manual said 23 ft/lbs when I checked it the other day.
maybe i'm just up too early.

What do I know, I put it on with air ........................ The part number quoted ir right, except that's not the number we use. The "OEM" is NOT part of the part number, and PET doesn't list it that way. The Cap'n

I'm sure I have a few in my box of engine gaskets and such. I'm happy to mail you one but you can probably get one quicker locally.

Whatever.... Pelican says "not available anywhere". Local VW parts houses say they can't get that part. Local VW dealer says they can get me the $7 seal, but they'll have to overnight it and pass along the $20 cost to me of course. I'm not paying $30 for an o-ring.

Fuch it. I have a solution and it won't leak a drop. Thanks for the help fellas.

I suspect an oil leak from behind the fan. Anyone know if I can remove the fan and hub with the engine in the car?

My motor is on the floor and 30 minutes ago I just checked the clearance for the purpose of installing the fan in between the front piece of tin and the fan housing.

Not going to be able to get it done without taking the front piece of tin off. Which by itself is easy enough to do with the motor out. I would think that you could drop the front of the motor a few inches and possibly be able to get that tin off. But you're going to have to drop it a little farther to get a hub puller in there. The factory puller may be smaller, but you'd have to have one I suppose.

But I haven't actually tried it. YMMV

Yeah, make sure the hub is not damaged at all, because if it is, your wood drift key will never last.

We call that a "Woodruff key". http://en.wikipedia.org/wiki/Woodruff_key

The Cap'n