if its old school dude, remove inner cable and grease it as you slide it back in the outer, use masking tape to hold calipers tight on your wheeland pull cable through the caliper as tight as you can and tighten, then pull brake lever as hard as you can a good few times, this will hopefully stretch any give in cable out, then undo the fixing bolt and pull cable as tight as you can again and pull lever as hard as poss, remove masking tape, if your wheel is straight the blocks should be clear of the rim and your brakes nice n flex free, it can take a good few rides before your blocks bed in, when they do, mask calipers back to rims and pull cble through again to minimise stretch as cable should be worn in. lots to do but well worth the effort