Trafficators Solenoid recoil?

And for my next topic !
I have picked up a SF 55 trafficator off Ebay, last week, Like rocking horse Poo as we say, but anyway, I now have three trafficators, non of which have a solenoid that is capable of lifting the arm without help,( Blue pill will not work here) I have done all the usual things including; cleaning. lubricating, making sure there are secure connections etc. and I have done a lot of research on trafficators, and have come to the decision that they will benefit from the coil rewind, there are people out there who will rebuild them for a hefty price, and it seems that any information on how to do this is not readily available,
I am thinking that I will take one of the solenoids out and measure the wire and order some of the correct type and have a go at rewinding one myself, unless I can find a service provider that will just do the rewind
Anybody got any experience of rewinding these coils or know of somebody that can do it for reasonable money or any other help and advise will be much appreciated

A friend had a trafficator rebuilt by a vendor in England. On return and installation, the flag raises and then sends out a smoke signal.

If you choose to make your own coil, be sure to buy transformer wire with insulation appropriate for the task at hand. I don’t know what “varnish” was used in the 1940s or whether modern coatings will handle the bends for the application. Could be a fun learning experience.

Hi Mike,

Sorry, ignore my ramblings about two coil structure. The only complications are two switches. One to indicate on the dashboard that the arm is extended and the other to light the lamp.


Check that your switches on the manette are clean and able to pass the required current.



Hi Pete
Haven’t got round to fitting the manette yet, however very close, the trafficators have two connections like you said, one to power the solenoid to lift the arm and once the arm is lifted it supplies power to the bulb, once that happens the connection on the other side or the trafficator sends voltage to light up the dash light if I am not wrong

Yes, the lamp in the arm and the lamp on the dash are switched on by two separate switches inside the arm. Neither one flashes, they are just on.
If the dash light fails to come on you know the arm failed to raise. Mine get stuck sometimes.

You are lucky to find any of these anywhere. The 8" ones are quite common and I noticed the Mk Vs went to 8" and added a decorative chrome filler piece above. Maybe they were originally thinking of the longer ones.

You might have a problem with a build-up of gunge on the plunger and in the bore of the solenoid. The clearances are small and it doesn’t take much to create drag. You can remove the coil by undoing the screw at the end and sliding it back. Thoroughly clean the plunger and lightly polish it with some steel wool and solvent, eg turpentine. Cleaning the bore is tricky but needs the same treatment and think of it as cleaning a rifle barrel so that everything is removed.

Don’t add lubricant of any kind and be careful to not overly bend the attached wires. After cleaning and before refitting the coil, test the freedom of the pivot by holding the trf vertically, raising the arm, then letting it fall. If it drops with a decisive and rapid swing, and latches, the pivots are good and free running.

I don’t suggest fiddling with the windings as it’s best left to the pros. As a young’un I used to watch my father rewind armatures in his workshop for extra pennies to support a big family. The wire spec is critical, eg gauge, insulation, no. of turns, winding and layering tightly and so on. Any deficiency could be a smoky conclusion, and these are too rare to make mistakes. If they are moving, but reluctantly, the windings will be good.

There is one thing about these that I ponder. These long ones have a heavier arm than the standard items because of the extra length added to the end. I suspect, without knowing how to check, that the solenoid coil is the same for both types, therefore the magnetic field is not stronger despite an increased load (moment/torque).

In saying all that, I’ve managed to get my tired and lazy ones up and running like a pair of old swingers, and found a box of the correct slim festoon bulbs. I’ve created an unexpected problem with one in that it falls so positively that it bounces off the rubber stop button and hangs out 5 or 10mm but quickly settles. The next step is to change the bulb wiring to flash on the same circuit as the other blinkers. I don’t want to go the lazy way by changing them to flashing leds which will be out of sync with the main set.

All great comments from above. I will just add that so many electrical issues can be attributed to a bad chassis earth. Clean those earth connections thoroughly! :+1:

Thanks all I will remove one of the solenoids and thoroughly clean the bore and rod and report back, they do click and try to move a little but not enough to lift the arms, is there a Ohms resistance to check ?

Success ! all three trafficators working now, removed and cleaned the solenoids on each one, cleaned the inside of the solenoid body, cleaned up the plunger and cleaned up all the electrical contacts, and it helps if you test them in the orientation they will be on the car!


I also found that the more times the current is activated, the stronger the solenoid action. Same with the horns - started off very pathetic :blush:

All old things need to be given a nudge to wake them up.

happens to me all the time… sometimes takes two nudges LOL