No-expense-spared restoration of a rare G4 1939 Mercedes Benz

The same applies to the fuel lines which had to also be specially manufactured. The clean, symmetrical layout of the cables in the chassis almost resembles a work of art. Numerous innovative features of the vehicle are evident - the driver is offered additional braking assistance in order to decelerate the massive vehicle effectively. A piston operated by a vacuum cylinder additionally acts on the brake pedal via a cable mechanism. This technical feature, including a leather sleeve in the vacuum reservoir, had to be fully reconstructed.

The designers of the G4 played it safe as far as fuel supply wass concerned: the car has two electric fuel pumps, plus a mechanical pump and, in case all three fail, the engine can still be supplied with gasoline from a spare gravity fuel tank. After the restoration, the chassis with all its components looked very much as it did in the 1930s, i.e. rather austere as the paint coat of numerous parts had not been sprayed on but applied by means of a brush, resulting in corresponding surfaces. This method was therefore also used in restoration, maximum originality being the top priority at all times.

The G4 has numerous electric functions and therefore a highly complex circuitry. Unfortunately, a wiring-diagram was no longer available so the entire electrical system had to be reconstructed with painstaking attention to detail and a new cable harness was manufactured, which proved to be a highly complex undertaking. For instance, the G4 features a central switch which shuts off all electricity consumers, with only the electric components required for engine operation still being supplied.

Every single switch on the G4 was dismounted and repaired, at times with the most delicate tools which are reminiscent of a dentist rather than an automotive expert. Even the pale blue illumination of the Virgin Mary badge attached to the cockpit is in working order again, thanks to specially modified miniature light bulbs. All gauges were overhauled, and the precision of the electric clock was monitored and adjusted over the course of many weeks.

Today, it indicates the time almost as precisely as a modern quartz clock. The orange-colored plastic in the direction indicators was beyond repair and had to be replaced. After intensive treatment, the tubular radio plays again as it did before. And when required, attention is drawn to the car by four horns - two for city traffic and two louder ones for overland trips – or a siren.

The bodywork remained largely untouched – the brief had been to refrain from cosmetic restoration. The specialists cleaned the paint coat and polished the chrome parts, but that was largely the extent of it. Only the lower sections of the doors showed signs of rust which was removed as a matter of course. The bodywork’s sheet metal is lined on the inside with stabilizing wooden elements, a customary construction for cars at the time. These wooden elements were in good condition and were therefore merely cleaned and impregnated with a special fluid to protect them from drying out. The interior reveals traces of the car’s age of more than 65 years but is otherwise in almost impeccable condition – not least thanks to the care lavished on the car by the Royal Guard. Gentle restoration work will, if at all, be carried out in Spain where people have plenty of experience in the repair of valuable horse-drawn carriages, for instance – an expertise from which the G4 will be able to benefit.

After the restoration of the royal G4’s chassis, the car was taken to the test track on the premises of the Mercedes-Benz plant in Untertürkheim for trial driving to check on the perfect functioning of all components.

After the tests, the finishing touches were added to the engineering and the last adjustments were made. Then came the great moment: the bodywork was mounted back to the chassis, repeating the act of “wedding”, as this is known in automotive lingo, and the G4 came back into being, 66 years after its first completion in 1939.

...continued