Wednesday, November 17, 2021

C3 Corvette Ignition Switch Rebuild

GM ignition switches of the pre-onboard-computer era, are inexpensive and, therefore, faulty original equipment switches are usually thrown away without a second thought. Especially when they look like the one below, from a 1969 Corvette.

But regardless of how bad they may look, these components can be cleaned, repaired, refurbished, or restored back to their original condition, although in this case, a complete restoration was not necessary.

By the way, the part referenced is the actual ignition switch, even though it is often confused with the key tumbler or ignition key switch as I call it sometimes. 

When you turn the ignition key, the key tumbler or key switch engages the ignition switch via a rod that pushes a block with brushes that make the contacts needed to activate the starter motor and then revert back to the Run position. 

Additionally, the key switch is also used to turn the car off (which also locks the steering wheel), and alternatively, you can also turn it past Off to the Accessory position if you want to listen to the radio, for example, while the car is parked and not running.

And even though this particular ignition switch is the one that came with the 1969 Corvette steering column I recently restored, most GM ignition switches from the 1950s through the'90s are very similar, mechanically speaking.

Removing the ignition switch with the steering column in the car is challenging, and you will have to drop the column to comfortably reach it and remove it.

The switch is held in place by two small screws (red arrows below), and once the connector (not shown) is unplugged, it can be lifted off of the actuating rod.


With the switch on the workbench, you can start the teardown procedure which requires bending three metal tabs outward so the plastic housing can be removed. There are two tabs (red arrows below) on one end...

... and one more (red arrow below) on the opposite end of the housing.

Since the housing is made out of plastic, you want to be careful to avoid cracking or breaking it, and the best tool for the job is a pair of Channellock® or tongue & groove pliers as shown below.

With the tabs open, you can carefully remove the housing and the slider block with the contact brushes. Be careful as there are ten small springs, four copper brushes, one roller pin, a small flange stud, and three tiny ball bearings, so make sure you have a container handy to hold the small parts.

The photo below shows the inside of the plastic housing. This part has the Start/Run spring in one corner and all the terminals, which are plastic-welded to the housing, so you cannot remove them.


The slider block, as I call it, houses a total of ten small springs, two of them a little larger than the eight that push the brushes.

I took extra care to handle this piece carefully since in addition to the springs there are three tiny ball bearings as well as a small flange stud (for lack of a better name). I did not want these small parts to land on the garage floor never to be found again.


Lastly, I removed the Start/Run spring so I could give every single component a good cleaning. The Start/Run spring is held under tension in a small cage at one end of the switch housing, so I made sure it would not fly out of there and hit me in the face.


With the housing out of the way, you can see how dirty and corroded the metal frame was. All it needed to be brought back to life was a good scrubbing with a steel metal brush, followed by a light sanding. And just because sometimes my quest for perfection gets the best of me, I threw it in the vibrating tumbler for a couple of hours.

A bead blaster would have been perfect for this job, alas I do not own one. And I also considered giving a couple of coats of paint, but I rejected that idea since the frame may also act as a ground for the switch and I did not want to create a bad ground for the sake of beautifying an old part that looks fine despite some rust pitting.


The switch terminals also needed some refreshing and I did that by filing each blade with a flat key file.


I also gave the two plastic assemblies a good hot-water-and-dish-soap bath in the kitchen sink.


And finally, to remove all traces of dirt and dried-up grease, I used a cotton swab and isopropyl alcohol.


The tiny ball bearings, springs, and brushes also received a good soaking in alcohol.


Since the switch brushes looked the worse for wear (I believe they are made out of copper), I used fine sandpaper to remove as much oxidation as possible so they would make good contact with the terminals.

Notice the domed shape. The dome rests against the terminals.


After all that wire brushing, sanding, and polishing, the switch frame turned out very nice. And the pitted areas will be covered by the plastic assembly.


I installed the Start/Run spring by compressing it with a flathead screwdriver, again making sure it would not fly out of there. Once the spring is properly secured in the housing, there's no risk it will fly out of there (two photos below).



Next, I applied generous amounts of lithium grease to the sliding block and installed the springs, brushes, and the roller pin at the end of the block. That one rests on the two larger springs.


With the sliding block in place, I also added lithium grease to the channels on the other side of the block and positioned the tiny ball bearings in them (red arrows below). I believe their purpose is to allow the block to glide smoothly over the metal frame.

By the way, the green arrow below points to the only possible location for the little flange stud mentioned earlier.


I finished reassembling the ignition switch by bending the three tabs back over the housing edges to secure it in place.


And this is the finished product! It looks mighty fine for a rebuilt 40+year automotive part. And even though I had no way to test it, I am sure it will easily provide another forty years of reliable service.


Installation of the ignition switch on the steering column is a matter of locating the sliding block slot, aligning it with the rod end, and then sliding the switch in place and attaching the two screws.



For a step-by-step video of the refurbishing process, from start to finish, click the link below.


Replacement ignition switches are not expensive. They retail for under twenty dollars or less for aftermarket parts.

And while aftermarket components are usually of good dependable quality, there's nothing like using OEM parts in your Corvette.

If you want to use parts that came with the car originally, as this ignition switch, for example, then repairing and refurbishing components is an excellent option.

As shown here and in the accompanying video, it just takes a few hours, some basic tools, elbow grease, and a desire to do the job right.

If all fails, you can always buy a new one, but there's a lot to be said about the sense of accomplishment of bringing an old component back to life.

I hope you found the article and video helpful as well as entertaining and, as always, thank you for following My 76vette Blog!



Product Links... (#sponsored) • ACDelco GM Original Equipment Ignition SwitchGM Ignition Starter Switch by Standard Motor Prods.Channellock V-Jaw Tongue and Groove Plier 6.5-InchKey File Set | 6 Pcs.

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