Stuck nut on rear derailleur

[Twilkes]

Attached is a photo of the underneath of a Tourney 7 speed rear derailleur. You can see the nut on top, that comes off fine, but the nut/washer that’s holding the cable in place ain’t moving at all.

Is that supposed to just slide off? Do I need to twist it? If it won’t move, is the only other option a new derailleur?

 

[alicat]

Pretty sure a new derailleur is overkill. I'm not familiar with that derailleur but it might just need a spray with WD-40 then a good yank after a while.

 

[Twilkes]

Yeah I’ll try that, hadn’t even thought of WD40 on it. I did have to replace a derailleur once because part of the screw-in cable housing broke off, at least it’s not Ultegra level kit though!

 

[Darius_Jedburgh]

Doesn't the washer have a flat on the inside? The shaft has a corresponding flat. The washer then is fixed in place and has a groove underneath that the cable sits in. The nut holds everything tight. The washer just needs a bit of force to lift if off.
(Picture isn't brilliant)
Allegedly.

 

[classic33]

A warm nail or soldering iron applying heat to the bolt, then letting it cool. It may break any seal that has formed.

It's a simple! nut and bolt, holding the clamp in place. Cheaper, and easy enough to replace rather than the whole derailleur.

 

[Ajax Bay]

The nut unscrews: you've done that. The tabby washer (notanut) underneath is just that.
Hit the bolt's end with a hammer: that'll loosen it. All 3 items are steel steel.
And the bolt will fall out (its shank immediately under the head is square, to stop it turning).

 

[Cycleops]

I always have a vice grip ready for moments like these.