chad valley ddn fordson major

[edd-1]

have bought a chad valley fordson major, the only trouble is that the clockwork mechanism doesnt work, could anyone help with advise on takin them apart, as far as a can tel the end of the spring has broken off, but the cover over the spring has 2 bent over tabs, which i have a nasty feeling will break off if i try and bend them to gain acess to the spring. has anyone mended one before?? advice welcome