A10 rear brake spring length

[MJM_58SR]

Hello all
Could anyone offer any information on the length of the spring between pedal and switch for a 1958 A10 please.
I bought the spring from Draganfly (I think) a long time ago. I'm using the slide type switch mounted directly to the frame. Clearly this isn't going to fit as it's way too short.
Am I Using the correct switch, how long should the spring be?
The bike had a shortish spring with a key ring ring and a cable tie to bridge the gap... probably not original😀
Any help as usual appreciated
Thanks
Martyn

[Willie Dee]

Jings must have the same guy who modified mine...same combo of parts, wrong spring, key ring ring and finished off with a cable tie. Was this a mod in a BSA service sheet?......Interested to know where the right parts can be sourced.

[RESTORER]

Hi, The free length on mine, a 1954 S/A A10, is 105mm in the same set up as yours by the sound of it, fitted to the frame. It is the same type of switch to the old one fitted and this looked original. I think I got it from D'fly, but as you can see I stretched it just a little to help the set up as it is a very strong spring, so maybe it was 100mm free when new.

[MJM_58SR]

Thanks for the replies
I think I'm there with it now.
There are a few different lengths so that explains why I have a short spring!