Rear hub bearing

First thing was to get the rear hub bearing fitted. I did this by hammering it in, using the old bearing as a drift. There's a lesson to be learned here - never throw any of your old bits away until you've finished. Here's the old bearing on top of the new, after installation:



When fitted, the bearing won't sit flush with the casing - it will be slightly raised.

Fit the oil seal, with the circular spring facing into the bearing. Oil seals like this should always have the side with the spring facing the source of the pressure.



Then fit the washer and flange to keep it all in place. I used nylock stainless nuts and washers but for some reason never took a photo:

Gearbox disassembly

Undo the six bolts holding down the end plate, and then lever it up with a large screwdriver or similar. You may need two. Or three. And some patience - mine seemed to be sticking a bit. When it's off , this is what you'll see:



At this point it's worth noting what you see so there's no confusion when you're putting it all back. Note the large gearbox shim sitting next to first gear:



And the layshaft needle bearing and shim at the end of the layshaft:



The gears just lift out. Again, make a note of which way round they go. I tied mine together with a cable tie after removal so I didn't have to work it out again later.





The everything lifts out with ease now. Be careful sliding off the sliding dog as there are two ball bearings and a spring controlling its movement. The balls have a tendency to ping out at great speed, so cover the assembly with a rag to catch them.

One thing that is difficult to remove and is often left in situ is the 'bearing track' and shim behind it, which hold the cluster and the cluster bearing in place.



The layshaft can simply be knocked out now:



And the bearing can be knocked out the other way with a bar and socket (assuming you've removed the hub plate and shim etc.)





My bearing felt particularly stiff when turning it by hand - it remains to be seen how this compares to a new one, but I do wonder if it was suffering from wear or damage of some sort.