Farmall Cub Switch Replacement

It was a cold, wet, dreary day in Central Texas. Perfect weather in which to replace the light switch I replaced last week. The first replacement was blowing a 20 amp fuse in less than a second when turned to the farthest right position. Fortunately I had added a separate fuse holder to the circuitry when the replacement did not have a fuse position. I spoke with the nice folk at Farmall Cub Forever and ordered a three position six volt switch which arrived a few days ago. This time I took pictures so you can see what I was doing. Again I replaced one wire at a time. The switch has a protrusion which fits in a notch in the console and I replaced it so the two were properly aligned.

 

I discovered it was easier to take the console off this time and I did not need a small monkey to reach in the confined space.  I did; however, forget that I placed a piece of board between the hydraulic housing and the hood/fuel tank. So when I started up the Cub to see how well it would run, there was an extra part, wooden of course, under the hood. Well… I now have head lights which burn dim and bright. I did not attempt to include the tail light as I am going to put a switch for it somewhere so the tail light is not always on when the head lights are on. What I noticed is that the ammeter, which is in the charging range and steady as can be with the lights off, goes into the discharge range and flutters rapidly and wildly when either dim or bright lights are on. I will seek the wisdom of those who know what that means. It cannot be good.

 

Tractor Boy

Farmall Cub working

Believing the original four position light and charging switch was mostly worn out, I ordered a replacement from Farmall Cub Forever. Nice folks with whom to do business. Yesterday I braved the cold here in Central Texas to enter my Tractor Building and replace the old switch. First I placed a block of wood between the hydraulic system and the hood/fuel tank to keep the fuel tank from collapsing onto something and maybe damaging the fuel bowl. Then I proceeded to remove four screws from around the top of the console and two bolts which fastened the console to the tractor body. Much easier to write than to do. There is very little room to move and I do not have a trained monkey to reach in there and turn a wrench while holding something in place. It turned out to be much easier to remove the part than to replace it later, but I was blissfully naïve then.

The choke rod, the hydraulic rod, and the starter rod all had to be disconnected from one end or the other to allow room to move the console back far enough that I could get at the four position switch. The wires were removed from the old switch one by one and fastened onto the new switch. Finally I soldered appropriate ends on a replacement 20 amp fuse holder and then put the new switch were the old had been. The new switch had no fuse holder such as was on the original switch. It seemed prudent to add a fuse going between the same points as had been protected by the fuse in the first place.

Once I had the new switch in place it was time to replace the console on the tractor body and screw it to the hood. Here is where I needed two little monkeys to help me hold things in place and screw or bolt it all down. It took quite a while to complete. Then the three rods were refastened where they go. Time to try it out.

Oh, Oh. As soon as the switch was put in the fourth position (far right) I heard a tiny “tic” and the twenty amp fuse was blown. After two more tries with the same result, I decided to avoid the fourth position and ask someone from the place where I bought it. I did that today and a three position switch is on its way. These old tractors such as my ’49 Cub were modified over the years. It seems I do not need a four position switch because I have a voltage regulator instead of the original “cut out”. I can say I got the lights to work. A final thing I did was to add hydraulic fluid to the hydraulic reservoir. From a new five gallon pail, I pumped for quite a while until it began to flow out of the observation/filling hole. So today I started the tractor and ran it a bit to warm it, the worked the hydraulic touch control lever back and forth at least a dozen times. All is smooth hydraulically speaking. The Cub started immediately and I fiddled just a couple minutes with the choke to get the engine running smoothly. It was forty degrees in that building and the Cub started within a couple seconds. As soon as I could get off the choke, I opened the sliding door and we cooled down to 32 degrees. Brrr.

 

Tractor Boy