VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Headlight switch nut size?

I only want to have to crawl my well fed self under the dash of my '38 once. I need to know what size the nut holding the light switch is so I have the correct wrench. Anyone know off the top of their head?

http://www.ebay.com/itm/NOS-GM-1938-Chevrolet-Headlight-Switch-/310419644182

Mine looks like this, is yours like this? It has a sliding hook type rod that works the switch. Are you wanting to remove both pieces or just the two nuts that will remove JUST the switch?

Yep, mine looks like that. I've not had it out but I believe there is a nut that holds the sliding lever in place as well as the switch body. Is there more than one?

The switch has one nut (1/4 inch)and a tab that holds in place. After you remove the switch part there's another nut that holds the pull rod to the dash. I can't see that nut without taking the switch out. I had to remove the ashtray housing to get to that nut. The vent lever is really close to the switch.

http://www.ebay.com/itm/1938-Chevro...ries&hash=item2ec18493fe&vxp=mtr

Hopefully you won't need a switch. A little pricey


http://www.chevsofthe40s.com/detail/11680/Chevrolet_Switch_Headlight.html

replacement switch is much cheaper. AND it has a fuse.

So that slot is a fastener location? Good to know. So the nut takes a 1/4" wrench or the thread is 1/4"?

The head of the nut takes a 1/4 inch wrench to turn it. I guess they're all alike,anyway that is what mine has. Removing the ashtray/holder helps see and get to things easier.The switch has a little tab that holds it in place as well as a screw w/1/4 inch nut head.

http://www.ebay.com/itm/36-37-38-Ch..._Car_Truck_Parts_Accessories&vxp=mtr

close up of switch

Thanks, I have a switch, just never had mine out before. All I had to go on was what I'd read of others removing theirs. So this tab, how does it come in to play? The frame of the switch slides under it?

I think so. It's been a year ago since I had mine out. I believe that's right. I found the ivory knob on the sliding rod on ebay and had it apart. It is hard to get to.While checking everything out in that area I saw a lightbulb (that was out) for the ignition switch. I didn't even know it had one. The wiring diagram didn't show it. It shines thru a tiny slot in the dash. See if you have one.

Mine has it. This wiring diagram shows it.

Ignition switch lamp. I guess I missed it. Did you know it was there? It's really a dim light. My bulb was out. I replaced it and was disappointed.

Replace it with a higher candle power bulb.

Got a good look at it today with the right light and mirror location. I don't see anything holding the switch in place but the nut on the escutcheon that the shaft slides through. The only thing approaching the size fastener that would have a 1/4" nut are the wire attachment screws and they don't use a nut. I have a short enough 7/16" wrench to fit through the ash tray opening but I couldn't get it on the nut and my shortest 1/2" wrench is too long to be of any use. I may loosen the lower dash support bar and see if I can move it out of the way. Frustration factor is too high for today.........

Apologies in advance for going off-topic a little, but each one of those ads that were posted implied that 37-39 light switches are interchangeable. My 37 requires a resistor to activate the generator. If the switches really are interchangeable, how do I get the resistance?

It's not a purely academic question, the resistor is blown in my switch and I would like to figure out what to do with it and thought I would take advantage of this thread. Thanks.

http://chevy.oldcarmanualproject.com/parts/1929_41/41cp049.html

37-38 ...1869613

What does it mean when it says do not connect resistence when using on FC models?

A 1936 FC (Standard) did not have a resistor on the light switch to increase charging rate.
A 1938 car would not have a resistor as it came with a voltage control - as did a 1939. A 1940 had a voltage regulator.

An FYI for anyone doing this in the future the nut size is 9/16" and it's a stamped steel nut, VERY thin and difficult to get a wrench on. I'm on the way to the hardware store to see if I can get s thicker nut that thread so if I ever have to do this again I can get a wrench on it.

That's much different than mine. Mine has a really small screw (1/4 inch head size). A 9/16 wrench would be really hard to turn in that tight place..

I had a photo of the switch in and out but Webshots is gone (FREE)and I never bothered to keep some of the hundreds of photos.Sorry.


http://debontools.en.alibaba.com/product/317802417-200692032/DB5100_Combination_Ratchet_Wrench.html

A ratcheting wrench won't work. The first pic below shows the switch with the original stamped steel nut. You can see there's no way to get a box end wrench on the nut. The second pic shows the nut that'll be going on it when I reinstall the switch.

I couldn't even see that nut without removing the switch. The 1/4 headed screw was holding the actual switch.

Not trying to be a smart arss but that IS the actual switch. The only other fasteners are the terminal connectors on the flip side.

http://www.ebay.com/itm/36-37-38-Ch...ries&hash=item43a4a735ca&vxp=mtr

That's the linkage rod that makes the switch work. The above link shows what is called the switch.

You're baffling me Steve. What do you think the rod in my pics is connected to? You don't see any similarity between the switch in your link and my pics? You're pulling my leg right?

Tiny, can you flip your switch over and take a picture to show what the other side looks like? I think that will be the switch Steve is referring to as being attached by a screw.