by Don MacKay
Ever been startled because the cure for something you struggled with turned out to be the rather obvious? That's what I recently discovered regarding the repair of turn signals that wouldn't cancel. I've replaced the spring that provides turn signal cancellation a number of times, in accumulating 160K miles on my '71 GTV. I've also replaced springs on a 101 Giulia Spider and a 105 Giulia Super. It was on the latter car that I recently discovered an important facet I'd been overlooking. If post-105's use the same spring or principle (I don't have any newer cars), the tip may work for later models as well.
Cancellation is actuated by a 3mm cylindrical spring, 10cm in length, which is wrapped horizontally once around the vertical sleeve of the steering shaft (this is all hidden from view, of course, by the steering column jacket). The turn signal arm is connected on both top and bottom ends to the coiled spring. Movement of the arm, say down for a left hand turn, loads the spring and rotation of the steering shaft as it reverses direction toward a center position during the negotiation of the turn, causes it to contract and pull the arm in the opposite direction, returning to its center position. For some reason (I think it's the clockwise direction in which the spring is generally coiled around the shaft), cancellation of left hand turns becomes noticeably more troublesome than for right hand turns, as time wears on. In fact, I've found that right hand turn may cancel perfectly while left hand turns won't cancel at all even after years of use.
You're smart and fix things yourself. You spend $5 for a new spring. After two hours of work you've replaced it, carefully reassembled things and go out for a test drive. Disappointment! The turn signal won't cancel much better at all for left hand turns. It probably works great for right hand turns.
Pay attention, because here comes a root cause of the problem: after years of wear a smooth shiny surface has been worn on the steering shaft sleeve where it contacts the spring. The shaft has become so polished by the action of spinning inside the coiled spring, that its spin no longer provides tension to contract the spring - even if you've supplied a fresh one.
Only five extra minutes is needed to reduce the risk of failure on this repair: simply roughen the polished portion of the shaft with a medium grit emery cloth. Clean the shaft, making sure it is free of grease (lubrication will inhibit proper action). Now the spin of the shaft against the coiled spring is more effective in providing tension on the spring. This simple extra step will make a difference. I wish I could say it makes all the difference. I can't because cancellation on those left-handed turns can still be troublesome 10% of the time - harking back to what may be a design weakness and my theory on the manner the spring is coiled around the shaft. I'd like to hear form others on this.
Incidentally, you need to pull the steering wheel, remove the bottom portion of the steering column jacket and remove the light switch from the shaft to gain access to sand the shaft sleeve. Contrary to what many people think, it is not necessary to pull the steering wheel to replace the cancellation spring on all 105 models, but it's tough work in a small space and you will have trouble gaining access to sand. Better to pull the steering wheel and ease the task.
Bouna Fortuna!