Mk 1 Square 4 coupling gear oil seal

[Duncan J Robertson]

Regarding the MK1 square 4 and the rear coupling gear oil seal.
This seal is not readily available that I can find.
Can anyone advise why I should not do away with the seal all together, and just use a sealed bearing, which are easily available.
The seal is only there to stop oil getting into the primary chain case.
Look forward to replies
Duncan

[will_curry]

A sealed bearing may not be quite as easy to obtain as you think. The inner of 1432-37
is slightly smaller than the other two bearings - only a few thou but enough to make
a difference.

[Duncan J Robertson]

Thanks Will
I just checked the bearing that came out with a micrometer, and inner and outer are both the same, I measured around the whole circumference of inner and outer to double check.
Possible wrong bearing installed previously ??

[will_curry]

Have you tried the Club's Twin Spares for a seal? I think you'll find the same seal 1180-49
is used on the 500 twins.

[Duncan J Robertson]

Will (excuse the pun Will) have a look, thanks

[JohnnyBeckett]

hi , give Gerof brown the clubs gearbox spares a try he is very good and helpful

[Roger Gwynn]

The .001" smaller ID roller bearing is not available, use a std one and Loctite. I have never seen a sealed roller bearing. In any case the seals on bearings are really only dust seals, they will help to stem the flow of oil but are no substitute for a proper seal.

[Duncan J Robertson]

Roger, thanks for your reply, and the use of loctite, but I think I will try fitting a sealed bearing as there is no oil pressure behind it.
I will be a guinea pig on trying this out, if it's a total disaster, and the primary chain case fills with oil, then back to the designed oil seal.
I will keep members updated if it all goes wrong.

[Duncan J Robertson]

Apologies Will, I misunderstood that you were referring to the internal diameter of the bearing in your previous posting.

[paul.jameson]

The coupling gear oil seal was introduced with the Mk I so the iron 4G didn't have one as standard, although they can be retro fitted. I have had two 4Gs. The first one (1948) was quite happy without the seal but they second (1936) most certainly needed it. So you might be lucky, or you might not.