WHAT THE HELL HAS HAPPENED TO MY REAR DERAILLEUR!?

[slomo]

Confirmed - 2mm allen key to get the pin out of this mech' (thanks Fluffy Chicken).
Remarkably, it all appears to be intact - even the little O ring has plenty of bounce.
It was pretty grotty when i opened it, but having given it a bit of a clean, it might :| just go back together.....
I'm going to leave it overnight (and maybe tomorrow as well) and attempt re-assembly soon

Watched some youtube videos on this - in the ones i saw, the cage moves freely, albeit at completely the wrong angle to the mech' body.

Mine was stuck solid - really took some effort to move it.
I was sure it was going to fall out in pieces when i got the pin out - you live and learn

 

[FluffyChicken]

Re:

Just be glad it is not the hanger bolt. They're really fun

 

[Woz]

You are on track there! Just take your time and be careful when you start putting the spring under tension again.

Another fun one is removing cages from newer low / mid end that Shimano definitely didn't want you to attempt.

viewtopic.php?f=41&t=413060

 

[slomo]

Just thought i should round this out with the news that the rear derailleur went back together really easily :shock:
I was so surprised i took it apart and out it back together again several times.
She's back on the bike and working like a dream
I'm bemused as to how it happened in the first place :?
Half expecting to have to add a link or two to the chain, even though i'm pretty diligent with these things on initial setup.
But even in 'big, big' gear (i know..... :| ) the mech is not overly tight.
Anyway, all's well that ends well - many thanks for everyone's help and advice - really appreciated.