You need to assess the usability and cleanliness of each part before you put it back on your car. Start by examining your fasteners, because many of these will need to be replaced. Chances are, you broke some of them when you were taking your car apart. Old bolts are especially prone to breaking off in their holes, and screws often strip their slots. Many nuts will be stripped of their threads, or their outside edges will be chewed up, and most of your washers are likely to be bent or out of round.

Removing broken bolts and studs is among the most frustrating things to do in your restoration. Typically, the threaded shafts have rust-welded themselves into their receptacles, and they will hold on with a tenacity that never ceases to astonish even experienced restorers.

To remove stuck fasteners, first remove everything around the bolt to see if you can get any kind of a grip on it. If you have only a little broken-off piece to work with, try a pair of big vise-grips cranked down very tight - but don’t start twisting just yet! Your best friend in this process is heat. Apply a pencil-flame propane torch around the stuck bolt, heating it several times. You want to heat the surrounding metal more than the bolt, if possible. Metal expands with heat and you want to break the rust connection between the bolt and the surrounding metal. You can try letting the bolt soak in penetrating oil overnight, but it rarely does any good.

If the bolt is broken off below the mating surface, you have fewer options. Drilling and retapping the hole may be your only option. You can try “Easy-Out” extractors, but these may also snap off. The rule with these tools is to use the biggest size extractor you can manage without completely destroying the hole.

If you have to completely drill out the hole, you’re looking at reassembly with a nut backing up the bolt, or tapping the hole a size larger and inserting a helicoil. This is simply a sleeve that is threaded inside and out. You enlarge the original hole to the next size up, get the right sized helicoil, and thread it in. Helicoils work well, and machine shops often insert them into engine blocks when they have this problem.

If you’re attempting a concours restoration measured to 1,000 points, you need to get exactly the right fasteners with the correct markings on the bolt heads and the correct nut design. Some bolts in specialty applications have a shoulder, offset head, or other unique features. Pay special attention to these parts and make sure you get the right replacements.

But if you’re working a less rigorous restoration, you can get away with using substantially similar hardware. And if you plan to drive your car with any vigor, you should seriously consider replacing critically stressed fasteners with modern high-grade nuts and bolts. As a rule, the harder Grade 8 nuts and bolts are used in tension stress applications (high torque values or the pieces in question want to pull apart) while Grade 5 bolts are used in shear applications, where the pieces want to slide sideways to each other.

For applications such as mating exhaust headers to your engine, consider using brass nuts. These have a very limited maximum torque before they strip, but they don’t rust!

Where you’re dealing with invisible nuts, consider using nylon insert locknuts. These will give you some peace of mind that your fasteners are not likely to come loose.

For non-marine applications, you should not need to invest in stainless steel fasteners, but they look great, so restorers often choose to spend the money.

The main thing about fasteners, especially if your project did not include all the fasteners you might need, is to have plenty of them. Your car probably uses 2 or 3 main sizes of bolt (7/16, 9/16, and 3/4, or 3/8, 1/2, and 5/8) and just a few other sizes here and there. So at a minimum, you should have a goodly supply of nuts in the appropriate sizes for your car and an assortment of the same size bolts in various lengths.

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