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MG MGB Technical - Turn Signal Question

Sorry to post so many questions, but it is amasing how many parts are not well described or even pictured in the manuals.

Did the turn signal system on the MK1 67 GT have a self cancelling system? If so, can anyone tell me how it works or even have a picture of it?

I figured out that the hole on the steering column goes down to match a small plastic bump on the bottom steering column cover. I also see that there is a small cutout on the edge of the column tube where another small plastic mipple on the turn indicator fits.

I figured that the turn signla wire wraps under and around the column and up over the top of the column.

The turn indicator switch has a brass finger sticking out that hits the steering shaft. I take it this where the horn button hits. Should it rub the steering shaft?
Bruce Cunha

I don't know about the 67 but my 65 does not have cancelling ability. I installed a radio shack buzzer that works well reminding me to turn it off.
Frank Baker

There should be a metal 'finger' that is screwed into the column which should cancel the turn signals by hitting those fingers on the switch and releasing the spring.
Mike MaGee

Don't know about the 67 GT, but my 70 MGB has self cancelling indicators which did not cancell when I bought the car. The best way to under stand the mechanism is to support the car safely on stands so that you can sit in the car und turn the steering wheel to watch how they work. The two plastic finger of the cancelling mechanism on my car were stretched to far out so they did not contact the bump welded to the steering shaft. The problem was fixed by placing an elastic band around the fingers to bring them back into the correct position. A more permanent fix was done by replacing the elastic band with a suitabley sised "O" ring. Sounds like your setup is different so this may not help you , but it may solve someone elses problem.
David Levy

Bruce. My oldest MGB is a 68 GT. So, I am not sure about the earlier cars. To the best of my knowledge, all of the MGBs had "self cancelling" turn signals. The MGA did not, but the switch was located on the dash as were the switches on the Sprite/midget in the early years. But, a column mounted switch has always indicated a self cancelling switch. It may be as David notes that the system is not working as originally intended. But, my experience is that the problem has been an out of adjustment situation, not a problem with the original parts. It is easy to pull the steering wheel, then, get it back with the two forks not engaging the self cancelling mechanism correctly. I have seen this problem on several cars. The best thing to do is to pull the steering wheel and check out what is actually happening, then report back. Les
Les Bengtson

They are self canceling. When they were new, we had a lot of problems with the plastic fingers breaking off; we regarded it as the only "Bad" part on the early B. About 67 or 68, we found out a "secret" part number, said to be fitted to european market cars, that had real metal fingers - end of problem. There is a Lucas part number change in mid 66 that may reflect this change, as we later heard that the good switch had been fitted to later US cars. As I recall, the good switch had headlamp flasher function, but the bad one did not. Find the number on the switch, maybe I can figure out what you have. Lucas had a nasty habit of changing part numbers, with the supersessions printed in ONLY the next couple of price lists. Price lists came out erratically, sometimes monthly, and after a couple of price lists the old number would vanish forever.
As Mike says, there should be a finger (in the form of a square headed brass stud with a screwdriver slot in it as I recall) screwed into the shaft.
The brass "finger" you describe sounds like a horn ground contact. It has been a long time since I saw one of these, and as you know there were a lot of column variations. Some columns had a brass contact ring on the shaft. What is the finger connected to? Does it go to ground, in which case it is grounding the column? Or is it connected to a wire (color?) in the switch? What colors are the wires into the switch?
FRM
FR Millmore

Bruce!

These owners before me have described the pin which is located at 9:00 on the steering column. This is an adjustable pin, held fast with a locknut. You have the ability to change its height by screwing it in or out of the column, then locking it with that nut. Make the adjustment so that it trips the fingers of the turn signal switch.

The more frustrating problem is to find this pin at 2:00 -- well somewhere other than 9:00 on the column. To correctly place the pin requires that you removed the inner column from the U joint.

Hope this little bit helps.

John

John H Twist

This thread was discussed between 11/08/2005 and 13/08/2005

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