How to repair a pot metal license plate lamp housing

Story by Tim Suddard • Photography as Credited

Broken parts are just a fact of life when dealing with older cars. Of course, fixing the problem isn’t always as simple as dialing a number and placing an order for a new component. Sometimes replacement parts are simply not available; other times, finances dictate that broken parts must be repaired.

We recently ran into a problem while working on a 1969 Triumph TR6. These cars house the license plate lamps inside a pot metal fixture that’s bolted to the bumper. Unfortunately, by now most of these bases are broken. The bolt holes tend to be weak and often fail.

If a replacement base can be found, the retail price is roughly $100. We couldn’t find a replacement in stock, so we turned to the next best thing: Fix the one we already had. 
While we’ll be discussing a specific repair for a specific problem, these same techniques can be generalized to fix a lot of different problems, especially those using cast pot metal components. Best of all, our method only uses about a dollar’s worth of materials.

Step 1:

Here’s the offending piece: a simple housing base for the license plate lamps. Both mounting bolt holes had been ripped open. While most people would throw away this component, we set out to make it as good as new.

Step 2:

Before recreating the bolt holes, we started by flattening and straightening the ends of the base. A hammer and dolly (or a similar flat, hard surface like the top of a vise) were the right tools for this part of the job.

Step 3:

Next, we gathered our repair materials: new bolts plus large washers. These washers—commonly called fender washers—are useful for recreating destroyed bolt holes. We simply lined up the washers so their holes matched the base’s original mounting points. Then, we marked their position.

Step 4:

The washers were a bit too big to fit perfectly under the chrome lamp cover—the part that sits over this base—so some grinding was necessary. We then mixed up some some two-part epoxy. We have been happy with Epoxo 88, an epoxy made by Fasco Unlimited of Hialeah, Inc.

Step 5:

We applied a coating of epoxy over the fender washers and around the base at the ends of our lamp housing. While neatness counts on this step, any extra epoxy can be ground away after it’s dry.

Step 6:

While waiting for the epoxy to dry, we turned our attention to the rubber gasket and chrome cover. We had ordered a new gasket from Moss Motors to replace our deteriorating piece. We trimmed the excess casting flash from the new piece with a razor blade.

Step 7:

Moss also sells the chrome lamp cover. Buying a new one was more cost-effective than rechroming the old one. (Quick tip: If the pitting isn’t too bad, renew old chrome pieces with some No. 0000 steel wool.

Step 8:

Our finished repair looks perfect and has held up for more than a year. The work took a bit of ingenuity and less than an hour of our time. As far as hard costs, the bolts, washers and epoxy needed to repair the base set us back about a dollar. Add in the new parts specific to this job—the chrome cover and the gasket—and we were able to do the entire repair for well under $100.

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