Replacing bearings on an m952 BB?

[ishaw]

Apologies if asked and answered but can this be done! They got the bearings in there somehow.

I don't want to destroy a BB to find out, hoping someone may have tried.

My theory is that it could be possible to do:

Remove threaded cup.
Place BB in a device that allows the axle to be pushed downwards, my theory is it should bring the bearing out with it.

Repeat on the other side.

Will this work?

There's probably the small matter of finding equivalent bearings to refit.

 

[old-school]

my friend did it, so i suppose it's doable..

 

[bikeworkshop]

The trouble is that the ball bearings wear slower than the races they are running on, so I doubt you'd get more than a 20% improvement.

If you can get it apart to clean it though, you might as well replace them, but the result could easily be disappointing

 

[ishaw]

I'm quite keen to give this a go as I've one which has no play but bearings are running a bit dry . How was it taken apart do you know? Not wanting to ruin anything trying.

 

[qianas]

You’re correct in thinking that the axle can be pushed downwards to press the bearings out. A bearing press or similar tool can help apply even pressure. Make sure the device you use allows the axle to move freely while pushing against the inner race of the bearing, so the bearing comes out intact.

 

[qianas]

You’re correct in thinking that the axle can be pushed downwards to press the bearings out. A bearing press or similar tool can help apply even pressure. Make sure the device you use allows the axle to move freely while pushing against the inner race of the bearing, so the Spherical Roller bearing comes out intact.

When pressing out bearings, it’s essential to apply even pressure to avoid damaging any components. A bearing press or a suitable tool can ensure that the axle moves freely while pushing against the inner race of the bearing. Just make sure the force is applied correctly and gradually, to minimize the risk of damaging the axle or the bearings.

 

[bikeworkshop]

If it's got no play but feels a bit dry, I'd try rinsing it through to clean it up best possible, then force some appropriate lubricant in there.

It wasn't built to be dismantled, so i don't think you'll be doing it any favours taking it apart if it's operational atm

 

[ishaw]

I may give that a go before getting to disassembly.

 

[FluffyChicken]

You have to admire Shimano, taking the sophisticated wider tubed octalink bb M950 with all it different bearings and seals etc, stiffness.
Then going, feck that we know how to make decent sealed square taper BBs so let's just copy that and stick the octalink ends on. Charge everyone a lot of money but not tell them we've now lost the benefit of that fatter through axle...
Just gaining the splined attachment benefit (which they already knew about from the early 80s when they used it back then)

And then ISIS who made a nice interface based around octalink ideas, but decided it had to copy the original octalink but cheap out on bearings (no roller bearings) and gain every disadvantage millions of tiny bearing have in the forces a BB has in an MTB style of riding.


Anyway I would guess it is the same method for square taper, you have to get the plastic cages out of the way. iirc not so easy on square tapers and a small entry hole, at least whenI tried and failed. And got the saw to it.

Are we assuming qianas is an AI bot?

 

[FluffyChicken]

But digging into the the brain recall (hazy)
You take of what cups you can.
You remove the thin seals between the axle and case.
You pull out the black plastic bearing cages.
You somehow get the bearings to one side enough so the axle can be pushed between them (towards the casing).
If you can manage this last bit without damaging anything, axle, race etc. You are good to go.
I think mine was un-90 and not a lot of room, you might have more room with that newer style casing.