Garage Door Coil Replacement

[ferkh10]

Have a problem with the blue coil on my garage door roller, the cable has snapped so I need to replace it.
Does anybody know if it is even possible to replace these and where I could get a replacement from?

Also, I cant see how to remove it, there is what looks like a cotter pin (circled in the pic below) holding it in but I've given it a good whack with the hammer and its not budging

 

[gregers]

ive recently mended my cable,like yours it snapped so got hold of some bike brake cable and some electrical connectors and joined all the cables up.works fine,then looked on the shelf in my garage and FOUND a whole new unit. so when it/if it breaks again then ill figure out how to change it.

 

[Burnerman]

The pin is a roll pin....not tapered but folded spring steel with a slot down the edge.
Its rusted in, but its possible to drive it out if the back end is supported.
Door repair kits are available from good builders merchants, and the cones are handed (that looks like an up and over Henderson).
The big problem with these is retensioning the spring afterwards.....basically it has to be wound along its length using an adjustable spanner and a locking tool that holds it as the spanner is repositioned. The coil is held to its shaft with an allen grub screw usually.
John

 

[honda]

If it is indeed a henderson then look here, also plenty of others if you google it.
http://www.ashleysonline.co.uk/CatList.aspx?CatParentID=5&gclid=CIaUlLGOhLcCFbMQtAodQ0cAwQ