Pull knob ignition switch

[drewpallett]

I have just started working on my grandfather’s 1940 9N tractor, which has been sitting for about 60 years. It has a pull knob switch on the dash lower left, rather than a key. I assume that this is an older ignition switch. I have read that old key switches cause too much electrical resistance because of corrosion, and should be replaced. I could install a new key switch, but would prefer to retain the old knob switch, if possible. Does anyone know if these can be successfully disassembled and cleaned up?

 

[markdtn]

What does the other side of the switch look like?

 

[Eman85]

The biggest problem with key switches is there are a lot of cheap junk out there that won't last and will cause problems.

 

[Ed S.]

I have just started working on my grandfather’s 1940 9N tractor, which has been sitting for about 60 years. It has a pull knob switch on the dash lower left, rather than a key. I assume that this is an older ignition switch. I have read that old key switches cause too much electrical resistance because of corrosion, and should be replaced. I could install a new key switch, but would prefer to retain the old knob switch, if possible. Does anyone know if these can be successfully disassembled and cleaned up?View attachment 166516

If it's a really old switch, you almost certainly can disassemble, clean and reassemble.

 

[used red MN]

I have just started working on my grandfather’s 1940 9N tractor, which has been sitting for about 60 years.

Hello Drew, welcome to YT! What else have you done to the tractor, do you know if the engine will even turn or is it locked from setting? Usually after that amount of time if not in a temperature controlled environment the cylinders rust and pistons stick. You most likely have bigger fish to fry than an ignition switch, we can tell you how to bypass it with a wire to just start the engine if it will turn. What kind of mechanical experience do you have? Knowing this will help us hone our answers towards your ability.

 

[Tall T]

If it's a really old switch, you almost certainly can disassemble, clean and reassemble.

So true for most old switches!
I just took a couple of 50's horn relays apart and cleaned those points. I service my two snail horns as well.
Just be gentle folding back the tabs that hold the backs on and don't bend them back any more than you have to to get the back off.
I use channel locks, diagonally to the tab, to squeeze the holding tabs inward and back down.

 

[markdtn]

The biggest problem with key switches is there are a lot of cheap junk out there that won't last and will cause problems.

Actual Indak USA made switches to replace 8N3679C that fit the hole are still available if you look (Allis Chalmers p/n 225310). They have spade terminals so you have to add the wires yourself.

 

[Eman85]

Actual Indak USA made switches to replace 8N3679C that fit the hole are still available if you look (Allis Chalmers p/n 225310). They have spade terminals so you have to add the wires yourself.

We've been down this road, the search function can find where we found the best switches to be Standard or NAPA, probably the same switch you mention in a different box.

 

[Kirk-NJ]

If truly a 1940 than the dash has been replaced with 1941 or later dash. Either way it would not have a pull switch. In answer to your question most of the times they can be taken apart and cleaned and reused. You might what to consider a key switch if you have young children

 

[markdtn]

We've been down this road, the search function can find where we found the best switches to be Standard or NAPA, probably the same switch you mention in a different box.

I looked for an old post. I found recommendations for KS6040, US64, and CSA1814. They may be good quality, but none of these look like they would fit the original hole properly. The Allis Chalmers 225310 part can be found in a few places as a USA made INDAK 2 post switch that will fit the original D-shape hole. Our host does not offer it so I'll not include a link, but here is a pic. You just add wires and go.

I got mine on Evilbay and they are $34 as of today. Note that not all 225310 are USA made so be sure you are getting what you pay for.