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MG MGB Technical - Replacing Rear Stop Lamp Socket

Recently I noticed my right rear stop lamp on my 1974 MGB was not working. When I tried to remove the bulb by pushing it in and turning, it would not move inward or turn. After fiddling with it off and on for a couple of days the lamp began to work again. I suspect the socket is going bad and I'll need to replace it sometime in the near future. Looking at the socket (on the left side) it appears like the socket is permanently affixed to the rest of the tail light assembly mounting. My question is; can I replace just the socket or do I need to replace the whole tail light assembly?
R Volkwein

Afraid you need to replace the whole tail light assembly
Iain MacKintosh

Hi,

I am of the mold that says lets try to fix it before binning it. Often there is nothing to lose and a lot of savings to be realised.

With the socket I think it is possible to remove it and fit a generic socket from an auto parts store. The existing socket has a ridge around it that sits hard up against the reflector and on the other side there are small tabs that have been bent over to hold it in place. I would carefully try to bend these tabs back to release the socket, or failing this method try cutting the socket from the other side. Once the socket is out you will need to use ingenuity to fit the new socket. I think they are mostly plastic these days, so you might need to open up the hole in the reflector some and also to provide an earth.

Herb
Herb Adler

Just spray penetrating oil in there and work it back and forth, eventually you will get the bulb out. A few days sitting does wonders! Then clean it up and use OxGard in the socket on reassembly. OxGard is a special grease for electrical connections, originally aluminum-copper contacts in mains supply boxes, available at home electrical suppliers. I use it on all electrical connections, and it has revolutionized my life.

If there is noticeable corrosion between the socket and the lamp base, you lose the ground. You can check it with a meter. This is a PITA. I solder ground leads directly to the socket to permanently solve this.

FRM
Fletcher R Millmore

I doubt there's much in a tail light socket that can't be refurbished. About the worst would be if the bulb is corroded to the socket, but if you've got it moving then that's not your problem. A bit of dielectric grease is a good preventative to just about all bulb socket issues, but that's for later after fixing what is funky. If you can remove the bulb, then push the wire or wires to that socket so the contact board is accessible. The wires should go through a gaiter that covers the trunk side of the socket. You can unhook the wires and push them completely through the gaiter, or just push them enough to get access to the contact board. A little sand paper should clear up any corrosion issues with the contacts. Make sure the wires are well attached to the back of the contact board. Check the spring for springy-ness, and lack of corrosion. Stretch the spring if insufficient pressure is responsible for poor electrical conduction. Replacing the contact board, contacts & spring is unlikely to be possible without a friendly swap meet, but most issues should be fixable. A broken contact board or a broken spring is the only things I can think of that can't be dealt with. The inside of the socket can be cleaned up with a small wire brush, but may require removal of the wires and the spring (at the very least to prevent damage to the wires).

If the socket itself is corroded to the point of collapse, or a bulb is frozen in place so it can't be removed with needle-nose pliers after breaking the glass, I'd recommend getting a whole new housing (the underneath part, replacing the plastic lens is a separate decision). It is possible to replace just a socket, but I think it's more trouble than it's worth.

If you're going to led bulbs, I highly recommend the afore mentioned dielectric grease (I recommend it for normal bulbs also). You're putting in a bulb that won't need to be touched for decades, even if you drive the vehicle every day. That's a lot of time for things to get frozen in place.
Dave McCann

This thread was discussed between 04/03/2010 and 05/03/2010

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