In contrast to conservation, which is like an unaltered historic document, the “restoration of a mass-produced vehicle without any significant historical associations can be justified if it is in poor and unstable condition or if a restored condition is required for educational purposes.”
A vehicle restoration is the process of reconditioning it from a used condition “in an effort to return it to like-new condition … can be refurbished using either original or reproduction parts and techniques.” Many antique and rare cars may not be able to have a true to original restoration done because some parts may not be available to replace or to imitate fully, yet with the proper research, they may be restored to an overall authentic condition. The objective is to preserve the historical aspects of the vehicle, its components, and assembly.
Restoration is sometimes confused with the term “restomod.” A restomod has portions of the car as they were when the car was first offered for sale as well as significant changes (updates). If any part of the car is updated, the car has been “restomodded,” and not restored, such as “a nearly stock-appearing vehicle that has been fitted with late-model chassis, drivetrain, and conveniences.” An “original restoration” puts a car in the same condition as when it was first offered for sale.
Another process is the re-creation, “a vehicle that has been modified to appear like another car or truck entirely, or like a more desirable version of that same vehicle.” Examples include taking a popular model and restoring it to a more desirable, but counterfeit, limited production or muscle car version. High demand for some special automobiles has also lead to sophisticated fake replica versions.
A complete restoration includes not only repair of the parts that can be seen – the body, trim, chrome, wheels, and the passenger compartment – but also the components that are not necessarily visible or otherwise evident, including the engine and engine compartment, trunk, frame, driveline, and all ancillary parts like the brakes, accessories, engine cooling system, electrical system, etc. Repairs are made to correct obvious problems, as well as for cosmetic reasons. For example, even if a wheel is covered by a full hubcap and not seen, and is structurally sound, it should have the tire unmounted and any required repairs performed such as rust removal, straightening, priming, and painting.
A complete auto restoration could include total removal of the body, engine, driveline components and related parts from the car, total disassembly, cleaning and repairing of each of the major parts and its components, replacing broken, damaged or worn parts and complete re-assembly and testing. As part of the restoration, each part must be thoroughly examined, cleaned and repaired, or if repair of the individual part would be too costly, replaced (assuming correct, quality parts are available) as necessary to return the entire automobile to “as first sold” condition.
All of the parts showing wear or damage that were originally painted are typically stripped of old paint, with any rust or rust related damage repaired, dents and ripples removed and then the metal refinished, primed and painted with colors to match the original factory colors. Wooden parts should go through the same meticulous inspection and repair process with reglueing, replacement of rotted or termite-damaged wood, sealing and refinishing to match the factory specifications. Pressure treatment with preservative may be considered to safeguard against future wood rot. Chrome and trim may require stripping and repair/refinishing. Fasteners with tool marks, damaged threads, or corrosion need re-plating or replacement-unless the car was originally sold that way. The frame must be thoroughly cleaned and repaired if necessary. Often abrasive blasting of the frame is the most expeditious method of cleaning, but it may still leave microscopic rust pitting behind, so should be followed up with a phosphoric acid ‘rust killer’ solution, before priming. Abrasive blasting using less abrasive soda or crushed walnut shells is less likely than sandblasting to cause damage to fragile items, while still removing corrosion. Acid tank dipping of the frame and or body followed by an E-coat primer after repairs is recognised as the most effective but also most expensive way to get rid of rust and to protect against future corrosion. The chassis frame should be properly coated for rust protection to at least match the standard of the original, to the highest modern standard would safeguard the time and money invested in the restoration.