Crank Seal?

What would cause a crank seal to leak?
Seal got replaced, and 15 hrs later, started leaking again.

Any thoughts?

Thanks

Improper installation, dirt, scoring of the surface, misalignment of
the cases.

On Mon, 10 Nov 2003 01:57:28 GMT, "Mark S Conway"
wrote:

What would cause a crank seal to leak?
Seal got replaced, and 15 hrs later, started leaking again.

Any thoughts?

Thanks

"Mark S Conway" wrote in message
news:cgCrb.157136$Tr4.422856@attbi_s03...
What would cause a crank seal to leak?
Seal got replaced, and 15 hrs later, started leaking again.

Any thoughts?

Thanks



I don't know about Lycoming but Continental has an old service letter, iirc,
for lightly sanding the crank where the seal fits with something like 320
grit at about a 30 degree pitch. I've seen it done at 45. Oil is "screwed"
thereby back into the crankcase, as the crank turns. I rebuilt an engine
which had this problem and it leaked copiously around the new seal. The
crank had a little wear and scoring from the old seal, but the tiny "mill"
marks solved the problem. No more leak. This should be done by a pro,
natcherly. And, of course, the pitch must be like your prop's. If it's in
the wrong direction you screw the oil out onto the nose and aggravate the
problem.

Mark S Conway wrote:

What would cause a crank seal to leak?
Seal got replaced, and 15 hrs later, started leaking again.

Check for a blocked crankcase ventilation tube.

George Patterson
If you're not part of the solution, you can make a lot of money prolonging
the problem.