rear oil seal, 3B

["Brandon Hull" <brandon@cardinalventures.com>]

A month ago I discovered that Audi only sells for the 3B ('91 200tq) a
re-designed rear oil seal and flange assembly for $70, while original seal
is available for $6-8 from aftermarket venders.   Since this redesign would
suggest some flaw in the original, and rear seal failure is addressed as a
common gotcha on the IA tech tips website, I was curious to know what had
changed.

In for a penny, in for a pound, as they say.  I bought the Audi assembly,
and, having installed it on Saturday, can now report on the differences.
In a word, the flange piece is identical. The principal difference is that
on the new piece, the rubber seal is permanently attached to the flange,
whereas on the old model, it pressed in and out.  Presumably, any leakage
problems which may have been occuring were between the seal and the flange
edge, not between the seal and the end of the crankshaft.  Interestingly,
the seal itself looks identical in size and shape, but not material.  The
new one appears all rubber, while the old one appears to be a laminate of
three materials.

My advice to anyone replacing the seal?  Go with the aftermarket
original-design seal, and use a gasket dressing or adhesive between the seal
and flange.

BTW, after all this, the old one appeared perfect, with no visible wear or
leakage, on a 100K engine.

A final note:  Bentley is nuts suggesting removal and replacement of this
thing using a special tool.  Just remove the flange, and it's a three minute
job.  Ditto the front oil seal.  As others in the archive have recorded,
don't even think of removing it with the special tool, just remove the oil
pump and punch it out from the back.  Then replace the pump, and press the
new seal on over the damper stub.  (requires some ingenuity with a short
pipe and washers)

IMHO, one explanation for the high price of Audi parts?  They have to
amortize the vast array of special tools designed, manufactured and
inventoried, but rarely actually used...

Brandon Hull
'91 CQ, 3B transplant someday...