There are two different seals available.  You want the thinner of the two, and it gets pressed in beyond flush with the edge of the case.  Iirc, they are 10 & 12 mm thick, though I'm a bit rusty on that. Usually, the parts guy wants to sell you the "better" thicker one. 

Karl Wolz
Sent from my electronic umbilicus

On Jun 14, 2013, at 4:03 PM, Joel Cort <joel_cort@YAHOO.COM> wrote:

> Jeff 
> This is real easy. Use no tools.  Load it up with light grease (not the black bearing grease with graphite)
> 
> Gently work it in all lubed up by hand. Push it in as far as it will go.  With the seal all lubed up it is a slippery little devil but will pivot right in.  
> 
> Sent from my iPhone
> 
> On Jun 14, 2013, at 12:34 PM, Jeff Lincoln <magikvw@GMAIL.COM> wrote:
> 
>> John,
>> 
>> Thanks for the reply. I tried to be as careful as I could putting that seal
>> in - actually truth be told, my buddy did it and I was very adamant that he
>> be as careful as possible - I'll do it myself next time. He's a great
>> friend, but he can be a bit of a "bull in a china shop" :)
>> 
>> I did not have the Flywheel machined - based on inspection by those I trust
>> (and know their way around avanagon) I held off on that. But I did install
>> the felt washer.
>> 
>> I'm not looking forward to pulling the trans again - but it should go a lot
>> easier this time since it was all recently removed and put back together.
>> All new Flywheel bolts and everything else was properly cleaned and greased
>> where appropriate.
>> Thanks,
>> 
>> Jeff
>> '85 GL (Gertie)
>> '78 Bus (Melissa) Patty's Bus