The cancelling ridge is the protrusion of a ring pulled over the steering column under the steering wheel. There must be millions of these in the wrecking yards, as most would not break. Just confirm that it is this ring that is broken, not the cancelling actuator at the bottom of the switch itself.

Once you have pulled off the steering wheel, consider swapping the indicator and wiper switches, to have the indicator on the right where it belongs on a RHD car. On my 1988 they had identical screw-hole patterns and were swappable with no effort, apart from the cancelling bit: note that the cancelling ring is in a different position for right-side indicators. There are two alternative notches on it that fit over a ridge on the steering column, so there is no guesswork involved. Of course, the wiper positions will be upside down, unless one finds a RHD wipe switch - I did not bother.

George Antony
(Brisbane)