"My turn signal lever broke and I can't find a replacement. What can I do? Does a basic Type III lever fit? What work is involved?"
Well that is a tough one, and one that seems to have plagued many Type 34 owners. I have seen and have heard of many fixes, ranging from using globs of epoxy to threading the inside of the lever and screwing it together. However, these fixes are hard to hide. There is another way.
On regular Type III's, 1967 and earlier, there were two types of levers. The differences are:
1) 1 or 2 contact bars (Type 34s and European Type III’s need 2 because of the side marker lights).
2) Different diameter mounting shaft holes, US specification being smaller.
See if you can find the right type for a Type III with side marker lights (European models), otherwise get the whole housing, and while you are at it get the signal canceling collar from the back of the regular steering wheel. The collar on your Type 34 is about 3/4" longer.
To do the next little chore, you must remove the column from the car. That entails taking off the steering wheel and removing the retaining ring to free the turn signal lever, and another so that you can slide the column out. You may also have to remove the key/lock assembly, or take the whole housing off in order to release the column, but try unlocking the key and taking out the column directly first. You must also remove the gas tank, so you can get to the steering coupler. Remove the bolt holding the coupler clamp in place, and slide the steering column shaft out of the coupler. (This will be a tight fit.)
Once the shaft is out of the car, you will be able to see what must be done to the coupler end of the column. Look carefully at the perpendicular cut which matches the retaining bolt and holds the column to the coupler. Measure up the column about 3/4" from the center of the original cut, and use a rat-tailed file to duplicate the old cut. DO THIS FIRST, so if you are not satisfied with your retaining bolt cut, you will still be able to use the column while your get another steering shaft (probably from the same wreck your got the Type III lever from).
After you have made your new cut, just like the old but, but about 3/4" closer to the steering wheel, cut about 3/4" off the coupler end of your column. You must also extend the groove in the end of the steering shaft so that your horn wire can come to the outside for re-connection. Now reinstall in your car. When you attach the replacement lever, you must use a thin screw driver (or some such device) to guide tabs on the self canceling actuators on the back of the lever into corresponding slots in the inside cover of the housing. You must also align the spring on the back of the lever with two tabs on the housing cover. If the spring is not aligned, the lever will not return or may even bind when used. If the small tabs are not aligned, they will bend, and not being in the slots in the housing cover, will not work properly. You can use the adjustment available in the dashboard mounting slots on the signal/key housing to adjust the clearance for your lever. Install the regular signal canceling collar on your steering wheel, reinstall the steering wheel, and away you go!
And another suggestion from Dirk Brogdon
I repaired one and it's lasted over ten years.Try using a long rod or stud that you can insert between the two broken pieces to hold it togeather and give it strength when done. Then use a two part epoxy or JB-Weld or something of the sort to bond the two pieces. Before it tack's smooth out the epoxy to conform to the arm. It can be painted to match the column. If you do it right you can hardly notice it's ever been broken.
Another suggestion from Clive Richardson
When I acquired my '66 it had a broken turn signal arm. I know these are difficult to obtain (I think they differ from regular T3s and even change over some year).
I have repaired mine by taking the wire out that runs to the headlight switch and using the space to epoxy glue a piece of square bar in as a splint (I tried round bar but it rotated in the glue). I also put some small hoops of thin wire in the wet glue to hold the headlight switch wires. As mine needed repainting I have managed to make the repair almost invisible.
Another suggestion from Mick Percy
I too had a broken turn signal arm but managed to repair it, what I did was to dismantle the arm and glue a tubular piece of steel inside the groove that the wires ran in with an epoxy resin type glue, I then replaced the wires running from the switch with smaller ones, so that they would fit inside the tube. The only problem here is that you may have to fit an interposing low consumption relay, as the smaller wires may not be able to carry the current, this is especially true if your car is six volt. I repainted the arm and filled the cracks and now you can't tell that it's been repaired. I suppose it depends on where the arm has broken as to whether or not you'll be able to repair it in this way, mine had (fortunately?) snapped in the middle.
The connections for the relay are quite easy, the two wires that originally went to the switch connect to a normally open contact on the relay, connect one of the new wires to an ignition controlled positive feed (with a 1amp in line fuse), the other new wire connects to one side of the relay coil. The other side of the coil needs to go to earth. Hey presto you've just saved yourself about 185 dollars, don't forget to clean up the switch contacts for the indicators and parking lamps whilst you've got it apart.
Hope this is of some help.