[Roadsters] Pinion seal

[Jim Anable]

I've got my 1970 2-liter in a brake shop.  The mechanic said that the 
pinion seal is "really bad," and wants to know if I can locate the 
part.  A local guy that I trust says that it's a fairly standard item to 
replace, once they pull it out to see exactly what it is.  But the shop 
is reluctant to do that.  So...

Does anybody know exactly what it takes and where I can source the part 
before the mechanic pulls the old one.