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Bill, This sounds like your spring pivots may be the (old) UNEF thread standard that were 18 threads per inch in this size range (dimensions are published on-line). Unusual, but not unheard-of for this era of manufacturing. Measure the thread inside diameter carefully (use a T gauge & micrometer) plus a thread gauge to verify the pitch, then consult a thread chart (table) before assuming the size. During this period, bolts were made on screw machines and lathes that had fixed gears to set the threads-per-inch, so some unusual combinations came about (such as the 14 thread-per-inch series).
Looking in my 1929 parts catalog, the front mount of the springs is not complex and the threads are likely to hold retainers that give the spring a vertical pivot but prevent horizontal movement. Check with John Cislak, as he advertised shackle set for the older models and they are likely to be quite similar. Even if you need them custom-made, they are not that complex.
In any event, measure the threads carefully and consult a thread chart (table) before assuming the size. Taps to clean up the threads in your spring hangers are available, but rather expensive. Herb
Stories like Anthony’s are why safety glass, seat belts and the other automotive safety features were invented and then made mandatory! One of the best things that AACA did for our hobby many years ago was to make safety glass and fire extinguishers mandatory for all cars exhibited at their shows, which set the standard for everyone else.
I have installed seat belts in cars from the 1950’s & 60’s that I fixed up as daily drivers, and will probably also add them to my Pierce this winter. However, the wooden floorboards will require a bit of careful engineering and reinforcement to get sufficiently strong attachment points, as the inertia loads of our bodies during a crash can be very large. Many years ago during Engineering school (1974), I had a summer job testing seat belt anchors in new cars and several failed by peeling up the sheet metal of the trunk floor, as the test load of about 600 pounds was applied to each belt.
Our cars are beautiful artwork, but some things about “the good old days” weren’t really all that good. Preserving and enjoying historical equipment is indeed a very enjoyable hobby, but learning how to make transportation safer and better is more important for society in the long run. Herb
Oivind,
The eccentric cam you show is symmetrical, so it can be actually be adjusted from either direction. On my 1929, there is a covered slot in the drum that is used to test the distance from drum to show with a feeler gauge and I strongly recommend you use it. I have recently been down this path with mine and it is not trivial. Keep trying to spin the wheel until it drags on the high spots of the drum as you adjust it. The other thing the feeler gauge can help you understand is whether the shoes have the same radius of curvature as the drum. re-curving each shoe before putting them back on the car was a point of adjustment at one time when re-lining the brakes.
Here is a web page for adjusting the Bendix 3-shoe brakes; http://dmacweb.com/tech/brakes/bendix/BENDIX.htm
There is also a manual on the web that I have printed out that goes into great detail on how these brakes work. There is a download, if you scroll down in this AACA forum: https://forums.aaca.org/topic/163474-three-shoe-brakespros-cons/
Getting everything to balance is not that easy, as there are about 4 variables on each wheel (eccentric, main cam pre-load, rod setting to balance between wheels and how round is your brake drum. Put the car up on jack stands and do the major adjustment on all 4 wheels to keep them in balance, so the car won’t pull to one side.
Since these drums are STEEL and not cast iron, you don’t want to turn them and normal brake machines cannot handle it anyway. Good luck with it – there is a lot of trial and error as you. Herb
I realize this is a “stale” thread, but wanted to add my $0.02 as I am changing the lights on my ’29 to LEDs. The best advantage is more light with less current. I ordered 1129 headlight LEDs and 1158 brake/tail light lamps from http://www.LEDlights.com. The parts arrived rapidly,fit well and are substantially brighter. I did notice that the focus of the headlights is different, but should still be acceptable for high-beam use. Adding the resister for dim lights should take care of in-town driving concerns.
The challenge now is the low (dim) setting for the headlights, which wasn’t working with the incandescent lamps either. Because of the lower current draw, I will need to experiment to see what voltage (and therefore resistance) will work best for the “dim” setting. V=IR is the electrical relationship. I did see another thread here that the resister is supposed to be inside the left frame rail, so that is the target location for the new one, once I size it.
Important note: LED is an acronym for Light Emitting DIODE. Diodes only conduct in ONE direction, so a negative ground lamp is not likely to work on a positive ground car. I have had this problem on AC applications, where we had too much flicker with LEDs (on a 25 Hz system) as it was only on during half the cycle. The vendor did distinguish his parts between positive and negative ground applications, so I take that as a strong hint in ordering.
Herb
http://https://www.ledlight.com/6-volt-positive-ground-automotive-led-lights.aspx
The size 12-32 is indeed real. MSC carries both dies and taps in this size if you need to clean up the ones you have or make new ones from stock. Amazon advertises a go/nogo thread gauge for this size.
No, it is not a common size; #12 is an oddball size anyway, but the UNC/UNF standard thread counts are 24 and 28 per inch. The most common 32 thread count is a #10 screw.
Best of luck,
Herb Tull
