Simplex Retrofriction shifter failure

[bigfatron]

On my commute to work this morning I dropped into a lower gear, only to have the cable twang and shift to the smallest cog.
It seems the nylon/plastic bush inside has given up, does anyone have a fix?
I can replace the whole thing, but are parts available?
Richie

 

[mdvineng]

Re:

Which part #

 

[pigman]

Re:

The springs were always prone to failure- part 3668 on the diagram. I broke several in my time, the symptoms were exactly as you describe.

 

[markyp]

yes, a common failure.
The fix was to thread an elastic band through the lever and tie the other end to the bottle cage....

 

[mdvineng]

I always regularly stripped and cleaned then re lubricated them, and they are still working.