A classic truck owner can and often does go to a lot of effort to upgrade their vintage truck's electrical system. For the guys with the mid-'50s trucks down this means ditching the 6-volt system with fat garden hoses for wires, and literally stepping up to a 12-volt system. The next step, and it's usually done when the switch is made to 12-volt, is to lose the generator and opt for an alternator. The reason to do so is generators do not start charging until the engine is well off of idle and starting to turn some revs. An alternator, especially an aftermarket upgrade model, is engineered to crank out enough 12-volt juice at idle so a guy can slow poke around all day and still have a fully charged battery. OK, this is all well and good, but what about those crusty old sealed-beam headlights with the tungsten elements and the Fresnel lens? It's true back in 1940 when the '40 Ford Deluxe first offered sealed-beam headlights it was a great improvement over the earlier types, but things have progressed in the last 69 years. The best way to pick up a lot more candlepower to illuminate the road and reap a cosmetic upgrade in the deal is to switch over to crystal-clear halogen headlights with parabolic lenses. The crystal-clear halogen headlights we used in this story were sourced from the fine folks at LMC Truck of Lenexa, Kansas. Because LMC Truck is a real stickler for selling products that are street legal in all 50 states, the headlights come with a high-efficiency 12V 60/55-watt replaceable bulb. For those of you who intend to use your classic truck for off-road use only (wink, wink) 12V 90/100-watt replacement bulbs are available through off road supply houses. Of course, with all the brand-new cars being sold with retina burning headlights we doubt 90/100s on an old pickup truck will ever be noticed. There's a good chance LMC Truck has a full-page advertisement somewhere in this magazine that lists an application for your truck. For this tech story we used the most common size headlight in the whole world for trucks from 1940-79, a 7-inch bulb. It's a pretty easy swap, but there are few places where a guy can screw up, so pay close attention the following captions and you should be fine.
The 7-inch sealed beam headlight...
The 7-inch sealed beam headlight bulb represents 99 percent of what's used on classic trucks. To remove the OE 7-inch sealed beam bulb from our '79 C10 the first step was to use a Torx T25 and remove the headlight door (surround).
As with this '79 C10 there's...
As with this '79 C10 there's always one last screw that might be hidden from sight and prevent removing the headlight door. Taking the time to take a closer look can save breaking hard-to-find trim parts.
After removing the special...
After removing the special factory hardware used to attach the headlight door it was a good idea to count what we had, and set it in a safe spot.
As is often the case, it required...
As is often the case, it required a little jiggling of the headlight door to dislodge it from the truck. Forcing trim parts can lead to breakage and follow with personal depression caused by screwing up.
Notice in this photo the 7-inch...
Notice in this photo the 7-inch sealed beam bulb has already been removed. It is very important to note the three Phillips head screws that hold the headlight retainer ring are positioned at 11, 8, and 4 o'clock.
If the Phillips screws at...
If the Phillips screws at 9 and 12 o'clock that control headlight adjustment are removed the headlights will become extremely out of adjustment, and real depression will ensue. In short, don't touch them.
After the three Phillips screws...
After the three Phillips screws are removed from the headlight ring, the 7-inch sealed beam bulb will immediately drop out of place.
The next step was to remove...
The next step was to remove the 12-volt electrical plug from the back of the OE sealed beam bulb by yanking with a slight twist at the base of the plug's wires. If you break it, you yanked too hard.
Here's the pair of LMC Truck...
Here's the pair of LMC Truck 7-inch crystal-clear halogen headlights with parabolic reflectors, and a really cool look that reminds one of the old Lucas Flamethrower headlights so popular in the good old days.
In the case of our '79 C10,...
In the case of our '79 C10, the shrouding around the 12-volt plug had to be trimmed off before the plug would provide a proper fit.
After the plug was installed...
After the plug was installed into the new LMC 7-inch halogen headlight properly and tested to see if the high- and low-beams operated, we reinstalled the headlight retainer ring.
The finishing touch was to...
The finishing touch was to reinstall the headlight door, and wait for the sun to drop.