Hitchcocks Forum

I'm interested in the instruction to take out the inside seal of a 2RS bearing when applying them to a gearbox application. From my limited research it would seem that a sealed bearing will generally out last an open one given the same load moreover modern manual gearboxes are largely sealed units. Why then do we expose the bearings to the detritus of a working gearbox rather than keeping them in their own sealed and lubricated environment? Thoughts please learned gents?

Simon,
I leave the seals in and have no problems

Ditto Norm. Ever since I pulled a BTH electric motor apart that was a Coronation model so 60 odd years old.. The bearings were perfect and had never been touched. Struck me that if they don't get dirt in them they don't fail.

I've not done this g'box mod as such but from an engineering point of view they are made like that so leave them like that ...........IMHO, naturally !!

Same from me, leave the seal in place, not all advice on here is good advice.

Bullocks Simon, Having removed the seal from various "quality" bearings only to find a light smear of lithium type grease within, i feel its a no brainer to have the bearing run in a oil bath if the opportunity presents… Good lube and temperature control of the bearing is guaranteed..

Wheel bearings or any bearing exposed to the elements of course ideally should be sealed against dirt ingress, no argument. But over time the thickener 10% of the grease will break down through oxidation, pressure and shear. Some of the grease will remain stuck to the seals and play no part in lube process until the temp in the bearing becomes high enough to remelt and redistribute the lubricant to the contact faces..
You said yourself the modern box is sealed so what dirt is going to get in?? Any metal particles from natural wear of the dogs/selectors will sink naturally to the box sump, to be removed on drain down and flush lets say every 20,000 miles or so..

Furthermore if i strip the box for check at say 60,000 miles would i reuse the bearings simply because they are sealed? or would i buy new ones for £20.00 Quid.. Like i said no brainer.. Well you did ask for opinions… cheers Gwilly

Gwilly, I can only assume that you buy some very poor quality bearings to post as you have, cars, bikes, caravans, and a multitude of machinery use sealed bearings and have done for many years.

Yes Dennis your absolutely right, every bearing has a designated purpose, But here were talking about a gearbox bearing which has been fitted for the specific purpose of converting the box to run in oil.. how can it make sense to isolate the bearing from this oil bath and instead use the small amount of grease supplied by the bearing manufacturer??…. I've opened sk and fag bearings and been amazed at how little grease is in there…. just sayin..

Sealed bearing = no contamination, open bearing = open to contamination from the gearbox, metal particles, water, any other dirt which always somehow seems to find it's way into a gearbox of this old design.

Compared to other uses wheel bearins, ETC, the gearbox bearing is very lightly loaded, when the bearing is totaly sealed and the lubricant cannot escape, how much does it really need?.

We are all of course free to make our own choices.

Regards Dennis.

Oh Dennis how can you say the final drive bearing is lightly loaded!!!! compress the rear shocks and tighten the chain at 60mph..
Now tell me that bearing isn't under load…. Ha ha Just thought this reminds me of the sixties, 100 bikes outside the cafe and people arguing the toss over all sorts of mechanical issues.. Guess this forum is the modern equivalent, the cafes now vanished into the mists of time...