B-axle assembly according to Shimano exploded diagram (No. 1).

Spares can be bought from CRC or tibolts if you’re feeling especially flush.

All well & good but HTF are you supposed to remove the old one? It spins freely, but there’s no movement back & forth, so I assume there’s some sort of expanding clip? Looking at the pic below, I assume something recessed in the groove below the head.

Threads are FUBARed & £6 to replace the bolt is more palatable than £35 for a whole new mech.

Yes there is a c-clip type thing hiding in there.

OK – that’s identified what’s holding it in place. How to get it out?

Something pointy to get underneath it and spring it out was my solution – of course that was probably the wrong thing to do but it did work!

Same here, I’m flummoxed by this. If I look in from the thread side I can see the c-clip. But what do I do to get it out? Do I push it down or try and lift it back towards the threaded side? Struggling.

Edit – not being responsible if you break it.