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Historic Motorized Vehicles
Malcolm Collum, Senior Conservator, The Henry Ford

The information in this fact sheet has been complied to assist in promoting the responsible care of historic motorized vehicles. The first step in the care of collections is to understand and eliminate or minimize conditions that can cause damage. The second step is to follow basic guidelines for care, handling and cleaning. These steps are based on the assumption that the vehicle will be maintained in a temporarily inoperable state but the functions of the vehicle will be preserved for possible future operation.

Restoration versus Conservation
Treatment Steps
Remove the Battery
Fuel Tank and Carburetor Lines
Drain Engine Coolant
Drain Hydraulic Systems
Brace Clutch Pedal
Grease Fittings
Drain Old Engine Oil
Drain Transmission and Differential
Lubricate Hinges and Mechanical Junctions
Use Axel Stands
Check Frame and Suspension Elements for Corrosion
Protect Interiors
Protect and Maintain Painted Surfaces
Safety Precautions


While many people collect historic objects such as furniture or books, very few expect, or want, those objects to be used with the frequency that the collectors of historic motorized vehicles aim for. As a consequence, the pressure to restore to original operating condition rather than conserve vehicles has meant that many original surfaces and materials have been replaced or altered.

If you restore a vehicle with historic associations, you are left with a generic example of a vehicle type rather than a vehicle that can be regarded as an unaltered historic document. However, 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.

This document will outline the steps required to maintain a vehicle in its existing condition with the goal of preserving original materials. The aim of these steps is also to preserve the vehicle’s intended function so that the possibility of operation in the future is maintained. All of the treatments are reversible and are intended to maintain the vehicle in its current condition.


It is often assumed that if a vehicle looks good on the outside, it must be fine on the inside. The preservation of a vehicle’s outward appearance is important, but the preservation of its functional elements is often overlooked. The steps outlined below should be performed on all historic motorized vehicles to ensure that their original appearance and intended function are preserved for as long as possible. You must have at least a basic knowledge of motorized vehicle mechanics to use this information correctly.

If it is old or dates to the period of use, you may consider keeping it and storing it separately. Even though batteries are considered to be consumable parts, historic batteries are rare and should be preserved. Some companies are making reproductions of historic batteries for shows but the variety is limited.

Drain the old battery and neutralize the interior with baking soda and water. Once the battery is neutralized, it can be reinstalled in the vehicle. Check the battery tray and clamps for any signs of corrosion. Be sure to check any suspension or frame elements below the battery for corrosion, which may be caused by leaking acid. Neutralize any signs of corrosion with baking soda and copious amounts of water. Surfaces that are already corroded will need to be thoroughly cleaned in order to expose and neutralize all of the acid residues.


Drain the fuel tank and clean the lines to the fuel pump and carburetor. As fuel dries, it leaves a tenacious “varnish” which will clog the system. Moisture that may be trapped at the bottom of the fuel tank will continue to cause corrosion, so leave the filler cap off for several weeks to allow for complete evaporation of any remaining fuel and moisture. When dry, spray the interior of the tank and carburetor with a light, moisture-displacing oil such as WD-40 or CRC 3-36. This will reduce the chance for condensed moisture to cause corrosion and will lubricate any internal mechanical components


Moisture left in the cooling system will promote corrosion.  Nearly all vehicle engines have dissimilar metal parts bolted together where galvanic corrosion will quickly consume the less noble metal.  Use a commercial brand cooling system flushing compound to clean out residues from the system.  Flush the system with a garden hose until the drained water runs clean.  Fill the system again with distilled water then drain. Leave the drains, hoses and filler cap open until the system is dry.  (The author adds water pump lubricant to the distilled water flush.  Water pump lubricant is emulsified oil that leaves an oil film on internal surfaces.  It appears to inhibit corrosion, but its effectiveness has not been tested.)


DOT-3 hydraulic fluid is extremely hygroscopic and will allow corrosion to develop within the system. This fluid should be drained and completely flushed with ethanol. If the brakes need to be operable, refill with DOT-5 fluid (silicone), which has a much longer life and does not absorb moisture. If DOT-5 fluid is going to be used, the rubber components should also be replaced. If the brakes do not need to be operable, flush the entire system with ethanol, dry the lines with compressed air, then flush with a light oil and close the system. The parking brake should left off to prevent the brake pads from adhering to the drums. A light application of oil to the brake surfaces will help prevent corrosion..


Install a bar to hold down the pedal or brace the linkage from under the vehicle. Depending on the type of clutch, the faces could adhere to the flywheel if they are not separated.


Pump all of the grease fittings with fresh grease. Use a synthetic grease since they are slower to degrade over time. Make sure that the fittings are cleaned before you add grease to prevent contamination. Old metal-soap based greases can become hard and block the flow of fresh grease. Remove all blocked fittings and clean out the old grease. Some greases are not compatible so if the existing type of grease is not known, it is advisable to continue adding fresh grease to the pivot until the old grease has been thoroughly “flushed”. Re-grease all fittings every four years. Early vehicles are often fitted with oilers. These fittings will usually have the same thread size as grease nipples. Where possible, exchange the oilers for grease fittings, fill the pivot with grease and replace the oiler. Grease will serve the same function as a heavy oil, but it will tend to stay in the pivot longer.


You may wish to refill the engine with new oil and crank the engine with its starter to recirculate the clean oil through the engine. Then drain this oil. Be sure to remove each spark plug and squirt in approximately two tablespoons of a thick engine oil such as 50 weight into each cylinder. Leave out all of the spark plugs, then rotate the engine one complete turn. Finally, spray some Marine Fogging Oil into each cylinder to leave a protective film of oil in the combustion chambers. Reinsert the plugs to keep out debris and moisture. Seal off the air intake with plastic wrap to prevent humid air from getting into the engine. Lubricate the cylinders and rotate the engine once a year. Try to leave the engine in a different position each year so that different valves are left compressed.


The small shavings of metal that accumulate in the bottom of the manual transmission accelerate the degradation of the oil. Refill these components with new oil. Jack up one of the driven wheels (typically a rear wheel). Rotate the wheel while an assistant goes through all of the gears, and then drain the new oil. This will help flush the degraded oil from recesses leaving a coating of clean oil on the internal components. Any breather caps should be sealed off to keep out moisture. Change the transmission fluid on automatic transmissions and leave fluid in.


A small amount of corrosion between two closely mated surfaces will act like a powerful adhesive and abrasive, so it is important that all junctions are lubricated with just a small amount of oil.


Stands should be placed under suspension elements to keep the wheels off the ground. As tires age, they become increasingly stiff and eventually turn brittle. The only practical way to slow the degradation of tires is to keep them out of ultraviolet light. Oxygen also causes rubber to degrade. Do not bother filling tires with inert gases such as Nitrogen or Argon since the fastest rate of degradation is on the exterior, which is continuously exposed to oxygenated air. Vehicles that are stored or displayed on their tires will eventually develop flat spots (permanent tire distortion) and lose air pressure. Place axle stands under the suspension elements to keep the tires just above the ground. The vehicle will look “correct” and, contrary to popular belief; the suspension will not become fatigued. Suspensions will only become fatigued through rough handling and corrosion to the springs. Some vehicles may need to have custom-made axle stands to provide the correct height for display. There are several companies supplying reproduction tires, but they are expensive and many historic sizes and colors are no longer available. Try to avoid moving vehicles on old tires. Use wheeled hydraulic jacks or Gojaks, which jack individual wheels.


Many vehicles were driven through salty roads and were never properly cleaned. Whenever the humidity climbs, these salt residues will promote corrosion which, given enough time, will destroy the structural integrity of the entire vehicle. Do not apply underbody coatings to an already contaminated surface. They will only hide active corrosion. The easiest method to simply stop corrosion from causing any more damage is to saturate it with a wax/oil solution. The efforts required to properly clean, inhibit and coat the underbody of a vehicle are significant and the costs are difficult to justify unless the structural integrity is already compromised to the point where a major restoration is required.

To stop corrosion from progressing, brush off all loose corrosion. Spray all areas with a thin wax/oil solution such as CRC-350. Allow this coating to saturate and apply a second coating if needed. Allow to dry for several days then apply a more viscous wax/oil solution such as CRC-400. This treatment should prevent further damage and it is reversible with mineral spirits.


Clean brightwork once, then protect it with a coating. Every time a metal surface is polished, material is removed, so it is important that the metal surfaces are thoroughly protected to maximize the time between each polishing. All elements to be polished should be removed and disassembled to prevent polish residues from collecting in recesses and to simplify the coating procedure. The cleaning and coating of one brass headlamp can take as long as three days. Use a mild polish such as Autosol, then clean off polish residues with acetone and mineral spirits before coating. Watch out for intentionally painted areas, particularly in stamped lettering. Never use a buffing wheel or any powered abrasive methods to clean brightwork. Nickel-plated surfaces can be very thin and are probably worn thin from previous polishing. Coat all brass and nickel surfaces with an acrylic such as Incralac for the best aging properties. Since this work requires the use of solvents, as well as experience in identifying materials and how to best treat them, consult a conservator. All chromed surfaces should be polished (if needed), cleaned with acetone and mineral spirits, and then coated with a microcrystalline wax such as Renaissance Wax. Apply a heavy coat of wax then allow it to dry without buffing. Use a hot air gun to slowly and evenly heat the part. When the wax begins to melt, spread it around the surface and let the part cool down. The heating process drives off moisture that may be trapped in corrosion pits and allows the wax to flow into these pits to form a sealing plug. After the part cools, buff off the excess wax with a cotton cloth. Only do this to pieces that are away from paint and plastic and can handle the heat from a hot air gun. If there are significant areas of iron corrosion under the chrome, a corrosion inhibiting wax/oil solution, such as CRC-350, should be applied before waxing to saturate and stop the corrosion.

Use extreme care when removing parts for treatment. Always consider the risks involved in removing and handling a part versus any cosmetic improvement that you might be seeking.


Light levels should be kept at a level (50 lux) that will protect the most sensitive organic material of the interior. Lights should be turned off when no one is present. Keep doors closed and locked to reduce the chances of an insect or rodent infestation and to keep out inquisitive visitors who may damage fragile upholstery or may be seeking a souvenir knob or emblem. Keep a “sticky trap” under a seat to monitor infestations. Good housekeeping and monitoring are the best pest control methods. Do not reupholster a vehicle that has its original upholstery. It may be the only existing example left and early fabrics and leathers are difficult to match. Slipcovers can greatly improve appearances and are usually unnoticed by the average visitor.


Cover vehicles in storage with a breathable, water-resistant cover. Vehicles on exhibit should be dusted as needed. Remove grime with a nonionic detergent such as Orvus. Oxidation can be carefully removed from painted surfaces with very gentle polishes such as those designed for polishing Plexiglas TM. Remember that every time the paint gets polished, some of it is removed, which slowly destroys its main function as protector of the material below. Eventually, the destruction of the paint will make repainting justified. Repainting is the most common method of making a vehicle “exhibitable” and this can often be justified if the current paint layer dates from a period after its historic association or if the current paint layer is badly degraded and exposing bare metal surfaces. Original paint surfaces that are uniquely decorative or decaled should always be preserved.


Obtain Material Safety Data Sheets (MSDS) for all of the materials mentioned above and carefully follow the handling recommendations. Gasoline and used motor oil are particularly hazardous so measures should be taken to prevent skin contact or inhalation of vapors. Use appropriate gloves and a fitted respirator with a filter approved for organic vapors. All waste materials should be disposed of in accordance with local guidelines; however, most local service stations are willing to accept small amounts of waste for a small fee.


The general public is growing to appreciate original, unrestored vehicles. In recent years, a “Preservation Class” has been added to most of the prestigious car shows. Once a vehicle has been restored its historic value (defined by level of authenticity–not original specification) has been compromised. Vehicles that are still in mostly original condition are becoming harder to find. This implies that their historic and monetary value will only continue to rise. Some of the procedures described above can be tedious, but they are essential steps that must be taken in order to preserve the materials, the intended function and the “value” of the vehicle.


Pest Control

A Guide to Museum Pest
Zycherman and Schrock, C.
American Institute for the Conservation of Historic and Artistic Works
Washington , DC 1988

Insects and Pests in Museums
David Pinniger
Archetype Publications, 1990

    Conservation Emporium
    100 Standing Rock Circle
    Reno , NV 89511
    775/852-3737 fax
    Renaissance Wax, Autosol

    Brit USA Imports
    39184 Venetian
    Harrison Twp. , MI 48045

    T & L Industries Co.
    300 Quaker Lane Suite 7
    Warwick , RI 02886 -6682

    Grainger Inc.

    CRC products

    Custom Aerosol Packaging
    PO Box 1411
    Piqua , OH 45356

    568 Broadway
    New York , NY 10012

    Synthetic grease, oils, water pump lubricant and DOT-5 hydraulic fluid are available at local auto parts suppliers