Feature: fix that cable
Replacing a cable can be expensive. Why not rather let the experts fix a broke one?
YOU never think about a cable until it snaps. It was recently front of my mind when the 1982 Yamaha IT250 I’m restoring needed a new clutch cable. Some older vehicles’ cables are difficult to source, while many modern units are expensive. The solution: fixing a cable. To research this feature, we visited repair specialist Cable Clinic in Cape Town.
The number of components in classic and modern vehicles using cables is staggering and includes the accelerator, choke, clutch, handbrake, speedometer, gearshift, window winders (manual and electric) and bonnet and boot releases.
A cable specialist is able to recondition and even rebuild all types of cables and usually stocks most of the components making up the unit. Those that are not in stock can either be ordered or manufactured in the machine shop.
Every cable is different, but these are the main components:
The outer cable forms the protective layer around the inner cable and is strengthened by an internal metal spiral allowing bending without pinching the inner cable. An inner sleeve provides a smooth surface for the inner cable to slide into.
The inner cable is the load-bearing part and comes in several thicknesses and forms depending on the application. The most common is 7x6, where strands are bundled and turned into a spiral; 1x19, where 19 strands form a cable (mostly for straight-line use); a speedo cable, formed by an inner and outer spiral in the opposite directions; and a push-pull cable needing a solid metal core to allow it to handle compression forces.
The ends may differ between applications and all carry an industry code. They come mostly in ball or cylindrical shapes.
Fixing a Cable
Old cables can be refurbished or rebuilt. The dimensions of the cable are important but more crucial to operation is the stroke length, especially when it comes to gearshift cables. According to Dillon Nel from Cable Clinic, the product supplied by a cable specialist is only as accurate as the information conveyed about the cable’s use. Providing the correct info first time round saves time and money.
When the outer and inner cables are chosen and cut to size, it’s time to fix the end points. This is a specialised process involving flaring the end into a rose shape after it’s pushed through the end piece. Finally, it is soldered and ground to create a smooth finish.
Speedo-cable ends are pressed with a die in a 20-tonne press to create the square shape needed for the drive. The end tip is then melted using an acetylene torch before it’s smoothed with a grindstone.