anyway so it arrived and i unpacked it, and it looked harmless enough...just a coil of metal, waiting to be crammed into a small container like so:
i removed the cableties and slowly removed the metal wire holding the spring together, and when i remembered: "hey, don't coiled springs have a lot of stored power?", the spring exploded outwards in 360 degrees. i got a nice mark on my arm as a reminder not to be stupid next time.
took me nearly 30 minutes to cram the new spring into the container, whereas the old spring took me only 5...all i can say is that this new spring is definitely able to store more force than the old one.
so there, it's done...i finally managed to fix this antique, i will take a video of it in action and post it up soon.