Dismantling Antique Tractor Magnetos

A guide to non-destructive dismantling and magneto restoration from a master of old tractor electronics

| February 2013

How to Restore Tractor Magnetos (Octane Press, 2011) is the essential guide to farm tractor electronics and offers the tractor restorer all the information needed to restore, repair and diagnose magnetos. Authored by the late Neil Yerigan, who was a master of working with vintage electronics, the book comprehensively covers how magnetos function as well as how to troubleshoot and repair common problems. In the following excerpt, Yerigan explains how to dismantle antique tractor magnetos non-destructively during the restoration process. 

Buy this book from the Farm Collector store: How to Restore Tractor Magnetos.

As there is more than one way to skin a cat, there is more than one way to dismantle an antique tractor magneto. I prefer the non-destructive system. The idea is that if you don’t break it, you don’t have to fix it. There are four requirements for non-destructive dismantling: time, patience, the proper tools, and good technique. If you have a Type A personality—aggressive, hard driving, impatient, a perfectionist—hire someone to do the work. If you are a Type B, or just naturally mellow, continue.

The nemesis of the repairer is the common machine screw. If you can master the removal of stubborn, rusty-headed, narrow-slotted screws, restoration is a piece of cake. If you lack the patience to do the job right, you are doomed.

The engineers who designed those tractor magnetos that we consider to be antique (or at least on the old side) really did a fine job. They used the best materials and technology available at the time. While some modern devices are designed to be thrown away, old machines are designed to be serviced or repaired. Of course, the engineers did not anticipate that, fifty or seventy years after the fact, some fool would try to resurrect and restore a magneto that had been abandoned in the dank corner of an unheated, dirt-floored pole barn since heaven knows when.

The main problem is that the tools that must be used to loosen the old rusty nuts, bolts, and screws just aren’t strong enough to do the job. Often, the fastener itself will break, leaving you with the problem of drilling it out and threading the hole. The only thing you can do is to patiently take the time and use the best tool for the job. Use a carefully honed technique, and hope for the best.