by: Corky Guenther

Our ’67 MGB is undergoing a complete refresh.  Part of that refresh is a stem to stern, ok headlight to taillight rewiring.  All new harnesses acquired.  If you’ve purchased a wiring harness lately you are aware that some of the original dashboard sockets are No Longer Available and they have been replaced with sockets for the more modern wedge type bulb.  The new harness for the MGB has these for two bulbs, the Ignition and High Beam indicators in the Speedometer and Tachometer.  If you have kept the original harness (of course you did!) you should, in your quest for originality, be able to reuse the original socket(s) presuming the original(s) survive in good condition.  There are a couple of options; the most obvious, and probably the simplest of which is to cut the wires on both the new and old sockets and splice the old sockets into the new harness, either with crimped butt connectors or by soldering the two wires together and covering the splices with heat shrink tubing – never electrical tape.  I, being anal as has been previously established, found another way.

The socket for the Ignition Light has two wires.  One from Ignition Switch (Battery) and one from the Generator/Alternator and is not grounded.   The socket for the High Beam indicator needs to be grounded.  The original is a metal socket grounded through the instrument case.  The new plastic one includes a ground wire.

Dealing with the Ignition light was a bit more involved than the High Beam.  The wire from the Gen/Alt is crimped and soldered to a tab which is part of the bulb case.  So, I heated the contact with a soldering gun and with a blast of compressed air blew out the solder.  This allowed me to spread the crimps and remove the wire.  As the manuals are want to say, the assembly is the reverse of the disassembly.  I used needle nose pliers to close the crimps and then soldered.

Next, on to the center contacts.  The center contacts of the original sockets are irretrievably attached (crimped) to the wires in the harness.  So, to use the original sockets without splicing, it is necessary to find a new center contact.  Obviously somebody makes them but I was unable to locate a source.  If you can find one, life might be just a bit simpler.  But I doubt it.  Good luck with that.

First it occurred to me that the hole in the insulator of the original socket through which the center contact passes is about 1/8” in diameter.   Then, while bouncing around through my empty mind, I landed on blind, AKA pop rivets as a possible solution.  I started looking for brass as that is the original contact’s material and Google brought up copper.  So I bought some that are 1/8” x 3/8” long. I suppose you could use rivets made of something other than copper i.e. aluminum or stainless steel. 

First, drive out the mandrel of the rivet.  Then split the barrel.  I used a hand held rotary tool.  Next cut the new socket off of the new harness wire and the old socket from the old harness.  Thread the old socket on to the wire of the new harness and crimp the rivet on the wire.  I used a Weather Pack terminal crimper but you could use any convenient method, just be sure not to flatten the barrel so much that it won’t pass through the insulator in the base of the socket.  You could also solder it.  Screw in the bulbs and they’re ready to install.

Oh yeah, I have a few (somewhere around 50) rivets left if you want to try this at home.