UN52 - Killing Me Softly

[Woz]

Sharing some Friday entertainment in the man cave. We've all wondered what's inside a Shimano Sealed Cartridge BB and how's it made. It's been done numerous times before to break in them, but here is one technic.

The subject for euthanasia is a knackered UN52 68/107mm. God bless.

Initially, I was going for the usual crow-bar angle grinder lump hammer approach. I started with a lump hammer first, but to no avail. I realised that is was best to coerce it to pieces rather than blugeon it to pieces.

Using ambassadorial skills and exploiting weeknesses, it can be pulled to pieces using just a Precision Srew Driver and Bench Vice. EDIT: Oh, and a drill

 

[Woz]

First is to remove the plastic bearing seal on the NDS using the Precision Screw Driver. This reveals a plastic cage keeping the bearings in place. Remove this with the Precision Screw Driver and push all the balls so they are all grouped together.

With the Vice, put the NDS in and tighten it up to ovalise the steel outer. This gives enough space to pick out the bearings one by one. I was lucky, the outer edge split making it easy.

 

[Woz]

Similar principal on the DS. But, there is the famous stupid pressed fit washer to remove first. A drill was required to "split / weaken" the washer, the a flat bladed skrewdriver to just pop-it off.

 

[Woz]

When the washer is off, remove the plastic seal and cage again. Group the bearing together. At this point, there is no need to ovalise the DS . The axel simply falls out.

 

[Woz]

The secrets of the Shimano Sealed Cartridge are revealed.

 

[Woz]

RIP

:cry:

 

[FluffyChicken]

Nice pics and write up where you do and so they don't have too.


If you remove both plastic cages from each side first then let/persuade the bearings to drop to one side the axle should come out with no bending and twisting.

 

[Woz]

Mmmh. Have you done this method? It's worth a try. Don't have any more victims, but that could potentially mean just a precision screw driver and drill.

 

[Tazio]

Like all the great game changing inventions it is in fact incredibly simple.

 

[dbmtb]

Just look at the amount of bearing contact area on the axle though! No wonder they almost last forever.