Rev counter drive 'O' ring

[Radlan2]

Hi Folks
      Further to fitting a magnetic rev counter I have oil being driven up the cable. The oil pump driven parts from ebay have no 'O' ring to provide a seal, also no scroll on the shaft to send oil back which the genuine part has. Does anyone know if there should be an 'O' ring, what the part number is and where in the assembly it fits?
       Thanks, Chris

[JulianS]

The later A10 r/c drive had O ring part 42 3039 fitted to a groove on the shaft. It is quite flimsy.

The first 2 photos show original A10 parts.

An A65 type housing fits and is a better part, it is recessed to take a more substantial O ring part 68 0588 which take care of the oil leaking out. The last photo shows a view of the A65  type with recess. I did have a problem with a pattern item which had a recess slightly larger diameter than the original.

If you have the recessed housing I would search the web for an O ring of the appropriate  size.

[Radlan2]

Thanks Julian, great display of knowledge as always.
    Chris Prov