you will have to get the drums off for a look at the shoes,check there is no oil/brake fluid contamination,try and grind the lip on the outer edge of the drum,this lets you adjust the shoes up accurately,replace shoes if worn,get the shoes adjusted first before you worry about the h/brake cable,you should just have a slight resistance after adjusting shoes,if your cable is still slack,think adjustment is under the h/brake lever shroud,10mm nut,may need a double depth socket for this,good luck
wickham
July 2010