Welding requires several precautions
ear Car Talk: I have an older pickup with an all-metal cab frame. There are numerous holes drilled in the dash and frame from old CB and gun rack mounts. I was told that the best way to fill these is using a MIG welder. What precautions need to be taken to protect the vehicle’s electrical system when I weld the cab frame? Thanks. — Ray
Answer:
I’m less worried about your electrical system than I am about your retinas, Ray. MIG welding is dangerously bright, and without proper eye protection, you could blind yourself.
After that, fixing the holes in the dashboard would drop down on your priority list because (A) you’d no longer be able to see them, so they wouldn’t bother you as much, and (B) you would have great difficulty securing a driver’s license.
But a MIG welder is what you want for this job. “MIG” stands for “metal inert gas.” It uses a thin wire and bathes it in an inert gas to push all of the oxygen out of the way. That keeps the surrounding metal from oxidizing, and allows you to seamlessly and smoothly weld metal together.
Which electronic components you need to protect depends on how old your truck is. If it’s old enough to have a metal dashboard — from the1950s or ’60s — then there aren’t really any electrons to protect. In fact, I’m pretty sure in that case your truck would have predated the discovery of the electron itself.
Then all you have to worry about is the heat you generate. So you’ll want to get under the dashboard and move away any wires that are in the vicinity of the weld. You also might take a picture of the wiring under there so that when you do melt the wires, you’ll have an easier time rewiring everything.
I also would use some sort of insulating material — like a piece of sheet metal — between the welding site and anything you might set fire to. Another good precaution is to do a little bit of welding, then take a look under the dashboard and make sure nothing’s glowing.
To be on the safe side, I would have a fire extinguisher nearby. And I’d wear a good pair of sneakers in case you need to run for your life.
If your truck is newer than that — say, 1980s vintage — then you will have some electronic equipment. In that case, you’ll need to unplug and/or remove anything with a printed circuit board before you send all that electricity through the vehicle.
All of that stuff is plug-and-play, so you should be able to just disconnect it and then reconnect it when you’re done. That stuff would include the electronic ignition components, the computer, if you have one, the radio, and maybe even the instrument cluster if it’s got a circuit board.
wipers off, they are supposed to sink under the edge of the hood, but the wipers stop in whatever position they are in. I was wondering if the wiper motor has gone bad or if it could be a solenoid or other electrical component that has gone bad. Please help diagnose my wipers. — Brad
Answer:
What’s the matter, Brad? Getting hard to squint through that 4inch opening at the bottom of the windshield while driving in pouring rain?
You need a wiper motor, buddy. All of the circuitry that controls the travel of the wiper arms, including when they “park” down in the windshield cowl, is packed inside that motor housing. Replace the motor, and your wipers should once again smear the entire windshield at high speed, just like they used to.
You can buy a new one for less than $100. Or you probably can find one in a junkyard for $20. Just be careful that the junk man doesn’t try to capture this car while you’re out back shopping.
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