Bicycle Repair/brake cable repair.
Have a little older MTB which has served me well. Fixing it up. I 'm not getting any tension on my rear brake cable. My bike is a Mtn. Shasta Sonora(4130 Chromopoly). Everything from the rear to the front assembly looks OK. But when I depress the right brake lever very little cable movement to back brake to facilitate braking. The little cylindrical end is crooked and where the cable connects into the metal tension(adjustment?) housing is loose not tight like the left front lever. Do I need a whole new brake cable? Havent been able to find specific info to what model or part number. It's gears are Shimano SL-my20.
Brake cable tension/slack is controlled by two factors: The fixed length of the inner wire portion in relation to it's outer housing sheath, and the return spring tension of the brake caliper arm(s) at the wheel. Can you pull on the brake cable inner wire at an exposed section of its run along the frame? If so, and you can produce some kind of movement of the wheel caliper, then the likely cause of your problem is that the inner wire length has to be shortened. This can be achieved either by loosening the cable's attachment point at the wheel caliper arm, and pulling some of the excess cable slack through before re-tightening the cable fixing bolt. Alternatively, you could remove the excess cable slack at the brake lever end of the cable system by using the barrel adjuster mechanism through which the housing passes. Loosening, ie, turning the barrel adjuster so that it increases in length, will have the relative effect of shortening the inner wire's length, thus in creasing the overall cable system tension. In either remedy, the goal is to set the cable system's length/tension at a point that allows for a reasonable amount of lever travel, without having the brake shoes/pads too close to the rim/braking surface as to hinder wheel rotation.