Another kink that can catch many backyard techs off guard is the old production method of layering. Some automakers in the past used to sandwich several layers of thinner sheet metal together for floor and other panels. This type of construction can make it pretty much impossible to address corrosion creep. The alternatives to dealing with this are limited to replacing the affected panels with a one-piece stamping, which may be possible to access depending on the popularity of the vehicle in question or a little more involved if fabrication is required.
Major kink number two involves the situation where different body panel materials are connected to each other; think fibreglass replacement panels. The debates on using fibreglass as a rust patch or a complete panel replacement are endless. Fibreglass and steel have different expansion and contraction rates when exposed to varying temperatures. This can lead to cracks and gaps developing over time. In addition, the bonding method of
That era introduced printed circuit board controllers to serve functions other than engine control. Onboard computers for airbag systems, automated HVAC controls, anti-lock brakes, and other functions started populating various areas of autos. Today, there can be up to a dozen or so of these brainboxes in an average vehicle, and just like home computers, they don’t like voltage spikes.
The first time I ran into the aftermath of an electric weld job gone wrong was when a vehicle wholesaler limped a 1988 Chrysler New Yorker into my shop, with just about every warning light on the dash lit up. My techs and I were scratching our heads when a seemingly endless list of trouble codes flashed on our scanner’s screen.
Liquid metal-weld paste or gel
This shouldn’t be used on structural components, among other things. The most popular brand of this type of miracle-bond is JB Weld. It really does have a thousand uses, but should
never be used to try to repair damage on any structural things like suspension control arms or sub-frames. It also won’t help much to repair damage that involves a threaded hole that takes a bolt, such as cylinder head spark plug holes.
Thread repair kits
These are handy, but don’t bet your life on them. Nothing frustrates a home-tech more than wrestling out a seized bolt, only to have it finally come out with threads from the hole attached. Now if it was a spark plug hole, and you’re installing the engine’s last set of plugs until you scrap the car, a thread repair kit is certainly better than replacing a cylinder head.