Mercedes 300 SL - Great Restoration Story

When Mercedes-Benz rolled out its new-for-2013 SL at the North American International Auto Show on Monday, it would’ve been really cool to show off the very first SL ever produced, in order to illustrate the heritage of the iconic sports car. (Especially because the SL will be celebrating its 60th birthday this year.) Unfortunately, M-B scrapped the first SL many years ago. But the company could drag out and dust off the next best thing: 1952 300 SL Nummer zwei.

Chassis number 194 010 00002/52, the second 300 SL ever built, has stayed with Mercedes-Benz ever since the car was hand assembled in 1951-1952. The car, which holds the distinction of being the oldest SL in existence, recently underwent an extensive restoration at the Mercedes-Benz Classic Center in Fellbach, Germany.

The company wanted the car to look as close to new as it could, without totally removing the 60-year-old patina. Interestingly, back in the day, the car was used as a training and backup vehicle for the race team, and was never involved in an accident, so the chassis and body panels were as straight as original.

The W 194 300 SL number two is one of the two vehicles built by hand in Rudolf Uhlenhaut’s Stuttgart-Untertürkheim racing workshop. The ensuing eight 300s were used mainly for racing in 1952 and were manufactured in the Sindelfingen factory, using pressed parts for the chassis – though they could hardly be called “mass produced.”

Number two looks almost totally hand fabricated: The chassis, the fuel tank, the exhaust, the seat frames, even the windshield washer fluid reservoir are the work of post-war German craftsmen.

Weight saving tricks were used everywhere on these machines, which tipped the scales at a feathery 2,336 pounds. The body is made of very thin aluminum-magnesium sheetmetal; parts of the front suspension have been drilled to make them lighter; the bellhousing, rear axle center section and steering box are cast out of magnesium; even the handbrake lever was drilled to shave a few ounces.

The restoration of the original bodywork was particularly complex and took about five months to complete, from May to September of last year. Mercedes-Benz’s experts strove to make the delicate shell look like it was formed out of one piece of sheetmetal as it originally did, working out previous restoration efforts and deformities that happened over the years along the way.

Replicating the car’s paint presented an interesting problem as the original nitro-lacquer “silver bronze” paint is no longer available and its use no longer legal. So the original paint supplier matched the matte finish paint as closely as possible in a modern water-based formula.

The 300 SLs famously ran a 3-liter, overhead cam inline-six from the Mercedes-Benz 300 (W 186) luxury sedan. For this reason, the engine block of this SL has the number “186″ embossed on it, while the modified cylinder head, on the other hand, bears the number “194″  Because the engine was intended for competition, engineers boosted its output to around 170hp by equipping it with three Solex sports carburetors and a specially ground camshaft among other things. The 300 SL engine also used a dry-sump lubrication system and was installed in the tube chassis at 50 degree left tilt so it would fit under the car’s streamlined hood. During the restoration, the SL’s original engine was completely overhauled and then run for 10 hours on a test stand.

The chassis of the W 194 was completed in the course of several months at the Mercedes-Benz Classic Center, with every single component cleaned, examined and reconditioned where necessary. The car’s nickel-plated front suspension was also reconditioned – the plating applied originally to make it easier for hairline cracks to be easily detected on the race track. When the rear axle was disassembled, the gears looked to be in virtually new condition, so they were reinstalled. Likewise, the original Alfin brake drums were tested, trimmed and reinstalled, and the original riveted wheel rims were shod with Dunlop D8 tires.

The interior of the 300 SL boasts new blue tartan seat covers, but the headliner and the rest of the interior fabric were cleaned and replaced. The aluminum seat frames were original and reused without needing any significant work. All of the other appointments, the wooden steering wheel, gearshift knob and gauges, are also original pieces.

Over the course of the nine-month effort, hundreds of details were attended to: The car was given new plexiglass windows and a new plexiglass windshield, provided by the supplier who made the original plastic pieces; The handmade three-pointed star emblem on the radiator was polished and reattached, as were the car’s original 300 SL emblems; and the rear license plate is an original, but the front plate was reproduced.

The finished product is an amazing piece of automotive history and a testament to the work Mercedes-Benz Classic is performing on old Benzes these days.

The original SL obviously doesn’t have much in common with the luxurious 2013 SL, but at least one aspect of the new car’s construction will impress purists: The latest SL’s body and substructure are made almost entirely of aluminum, making it 275 pounds lighter than the previous roadster.