Hi Guys, I decided I would do my bit to save the planet, and fit a sealed bearing to the output side of the gearbox main shaft of the M20 Im building .
As I set too I wondered if I should remove the seal on the inboard side of the bearing to allow better lubrication or to leave both in place and rely on the enclosed grease to lube the bearing for the next seventy years ?
Any thoughts on this would be appreciated. john biggs.

email (option): johnabiggs@talktalk.net

Hi John
I have had great success in both avenues throughout all sorts of industrial applications. I have run my own bearing co for over twenty years. The usual reason for removing the inner seal is that an oil lubricated bearing does run better at higher speeds.
For this, I would remove the seal, and this is what I will do when I rebuild my own.

Regards
Darren

email (option): dwrudd@lineone.net

hci im just building my box on my wng and bought sealed bearings but i openned them up to keep as original peace of mind is my thought .

email (option): m.wales10@ntlworld.com

The countershaft sprocket of an M20 could hardly be said to rotate at high speed!!

email (option): n.gentner@bigpond.com

I've just replaced 2 drive bearings on M boxes. I used rubber sealed (both sides) & like the fact it keeps the bearing full of lube even when the bikes sitting idle, gear oil is lower than the bearing & M boxes can get moisture in the area above oil level.

Neal

I said the "usual" reason. Not referring to this application, sorry if that was not clear.
There are many more to take into account. But rather than trip through the list on here, I would still suggest that open on the inside is best. But it will work both ways, as I said also.

If you want the long explanation email me.
Darren

email (option): dwrudd@lineone.net

Hi,
i think that if you leave both seals in place, there is the risk that the bearing over a period of time runs full of oil, wich can't get away once the bike is started again.
Ik would take the inside seal off.
M.

Michael, the bearing fits between 2 large oil retaining washers which completely cover the seals, I can't see how a seal could become displaced, its not really physically possible.

Darren, this has previously been discussed alot on the forum & a search will bring up good info, .. if you have several reasons not to leave both seals in, you should post them here surely, part of a forums purpose is to throw ideas arround.

I take the route of removing the inner seal. But my uncertainty as to whether it is worth doing, stems from years ago from the advice from 'R&R services' regarding the rear mainshaft bearing on my Willys Jeep gearbox. The tendency with the Jeeps is to pump the gearbox oil into the transfer box through the bearing. R&R sold a sealed bearing to eradicate the problem and they recommended that you leave both seals in. I think their bearing had metal shields and they maintained that the oil would seep in anyway. The other fact of the matter is, that the bearings are greased and sealed for life!! Ron

email (option): ronpier@talk21.com