Brake light Wiring problem continued

[Russell Reay]

Hate to start a new thread, but can't see how to attach a pic in a reply

"JaJay is correct about some of the stop light switches being being poorly made. On the switch I had the rod would slip inside the case and short out. Corrected it by soldering in brass tubes at each end of the case so the rod could not slip out. Have not had any problems since rebuilding about 2009."

This is the innards of my switch. It certainly appears to be 90 yrs old. I understand Jay's description of how it works, but I don't see the flaw in this unit.

 

[jrelliott]

I think the insulator on the rod at the left end of the spring should be on the right side of the copper contact. You can see the wear on the insulator on the top and the copper contact. It also appears that there was a piece at the end of the contact that broke off.
The switch is different than the one on my '28.

 

[katy]

can't see how to attach a pic in a reply

When posting a reply, click on "Go Advanced, then click on the paper clip icon near the top of the screen.

The switch in your picture is junk, replace it with a good one.

 

[Russell Reay]

Thanks for the tip re: Go advanced. As others have observed, the good switches are out of stock, but I can use a cheapo to get started.

 

[Canton_Model_A's]

Found this one on Snyder's Page:
https://www.snydersantiqueauto.com/00cad32cb6f8c24590f8238e8bb9b95c/product.htm?pid=976658&cat=41728

 

[JayJay]

Found this one on Snyder's Page:
https://www.snydersantiqueauto.com/00cad32cb6f8c24590f8238e8bb9b95c/product.htm?pid=976658&cat=41728

That’s one of the cheapies. It will get you by, for a while. But what you want is either a good used one or one of the good ones like this one. Note the brass bushing on the shaft, which isn’t present on the cheapies.

JR, I believe the 28s used a switch that bolts to the ******. The later cars used one that bolts to the frame cross member.

 

[Russell Reay]

That’s one of the cheapies. It will get you by, for a while. But what you want is either a good used one or one of the good ones like this one. Note the brass bushing on the shaft, which isn’t present on the cheapies..

Mine is this style and has the brass bushings, but pretty worn. What is the significance of the bushings ? Are they just to reduce wear of the shaft in the housing over time? I can't see an electrical function.

 

[JayJay]

Mine is this style and has the brass bushings, but pretty worn. What is the significance of the bushings ? Are they just to reduce wear of the shaft in the housing over time? I can't see an electrical function.

Without the bushings you have steel shaft rubbing on sharp edge of the steel housing. That will wear both the shaft and the housing, causing misalignment and eventually binding. It also sets up a potential for rusting the shaft and the housing together.

The brass bushing prevents that by having a lot of softer material (the bushing) for the shaft to ride on, and isolates the shaft from steel-on-steel contact with the sharp edge of the housing. It also gives you a surface to hold a drop of light oil periodically.

Correct, there is no electrical function. Just good mechanical design.

I recall a thread from the past where someone took one of the cheapo switches and added brass bushings. Straightforward from a machining standpoint but a bit of work.