Rear Derailleur advice

privateBeavis

Hi my rear derailleur seems to have seized up (the joint circled in the image). I was thinking I'll just go pick up a new one and put it on myself. So my question is are most derailleurs standard enough that I can just go buy one and fit it myself? Can you tell from the picture is that standard rear derailleur?

Plus anyone recommend where I can buy a cheap one (bike not worth spending much money on it!) in Dublin city centre?

damoz

Id try cleaning it and de-greasing it first. It looks like it hasnt seen a rag or lubricant in quite a while !

Joff

I'd agree with DAMOZ, take it off and leave it soaking in Diesel overnight, suspect it would be free in the morning.

privateBeavis

Thanks guys, I'll try that first so!

Dr_Colossus

That's an old style derailleur which I've seen and repaired my fair share off. I'm guessing you'd probably be looking at a minimum of €25 to buy a new one off the shelf and not sure if the bike would be worth spending that sort of money on.
It's well repairable though, if soaking in diesel doesn't free it out which I'm presuming it won't if it's rusted and seized then take off the little plastic black cover. Underneath you'll have a surclip keeping the shaft with the S bend from slipping out of the derailleur housing. Take off the surclip and then try and pull the shaft from the housing while twisting and freeing with some oil. If completely seized you might have to get out the gentle persuader (hammer) and give it a few taps. The shaft is spring mounted to keep tension on the chain so don't keep rotating the shaft in one direction once it starts to free itself or you run the risk or breaking the spring. Once removed file/sand down the rust on the metal shaft and smooth out the inside of the brass housing. Oil and replace ensuring the spring is mounted correctly and replace the surclip keeping it in place. Replace the plastic cover and happy cycling.