At last ! Mention of "a tube" ... I have been trying to figure out how to replace the clutch cable on my CC Zero as the old one frayed and snapped as it had not been properly routed around the pulley wheel at the front (this does not apply in a standard 126) and nowhere could I find mention of this guide tube that is welded into the central tunnel. Having got the new cable, I too found that the pedal end nipple/hook was too fat to go along the tube, leaving me wondering how on earth the thing could possibly be fitted.
There seems to be no mention at all of this tube in the Haynes manual, and I confess to being a little concerned about reducing the diameter of the pedal-end nipple. Is this normal practice ?
It might be easier on the standard 126, but on the CC Zero it seems difficult in the extreme to see exactly where the end of the cable goes in the route between the engine/gearbox area and the rear-most end of the interior central tunnel.
At present I have the old cable c/w frayed end a few inches back inside the long guide tube (I had to pull it back in order to see if the new cable's nipple would fit through the tube). Sensible practice I guess would be to somehow get this forward and exposed again, then attach a thin wire to it before pulling the old cable c/w attached wire out of the rear end, and then using the thin wire to pull the new cable through from the back of the car towards the front.
I can see me having to remove half the interior to get to all this

Is there any really neat trick anyone knows for getting the new cable located without dismantling half the vehicle for access ?
Thanks