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HomeBuying a M-100 - FAQ

Frequently Asked Questions About

Buying a M-100 Powered Automobile


Buying an M-100 Car
Research, research, research! The M-100 powered cars are among the most complex (pre-electronic) mechanical devices ever put forth on the asphalt. Parts are not available at your local NAPA store. Mechanics are few and far between. Unless you are one of the few M-100 experts worldwide, you want to buy the absolute best M-100 car you can in an attempt to maintain your wallet and your sanity.

Once a car has been identified, through local ads, Hemmings, or the Internet, call the owner to get as much information as possible prior to visiting the car in person. This, of course, applies to any used car purchase, but in the case of an M-100 car, is especially important. If the car is an original-owner car (rare), or has recently been serviced by a mechanic well versed in the M-100, you may have found a car worthy of a closer inspection.

Items common to all M-100 cars are the air suspension (hydropneumatic in the case of the 6.9). If the car is sitting low or kneeling, suspect potentially major suspension problems. 600s also use a very complex hydraulic system for window/seat/sunroof/trunk controls. Check door sills for hydraulic leaks. Getting the hydraulic system right is not an easy or inexpensive task, and is probably not something even a seasoned mechanic wants to attempt.

The drivetrain of these cars are actually very bulletproof. Unlike other cars of this era, it is not uncommon to hear of an M-100 car travelling in excess of 100,000 miles with minimal engine or transmission problems. The mechanical fuel injection of the 6.3 and 600 are generally reliable, but expect to rebuild the pump at some point as they all eventually leak. Also, unless you are buying a museum piece, consider converting the breaker-point ignition to one of several electronic systems available.


Finding a Mechanic
The M-100 Safety Net (available to members only) is a great place to start. This list includes mechanics and parts sources successfully utilized by M-100 members. Unfortunately, most Mercedes-Benz dealerships are NOT great resources, as the mechanics familiar with these cars have long since retired. If you have a relationship with the dealership, you might inquire as to whether any of the retired mechanics still work on M-100 powered cars.


Painting an M-100 Car
This section will surely be debated among owners, mechanics, and body shop workers. However, consider the following when deciding whether to paint a car:

·  Originality is highly coveted, especially at car shows and at resale time; don't repaint if you don't have to.

·  If the original paint is just faded, there is no reason to strip the car to bare metal. Sanding and priming is perfectly acceptable in many cases.

·  If you do have to strip the car, because of previous repaints or the need for extensive body work, do not sand blast the car — use plastic media blasting. If you have a 600 DO NOT bead blast the car — the debris will foul the complex hydraulic system. Use a chemical stripper.

·  It is generally agreed that the European paint formulas are preferable to more common American paints. Brands commonly recommended are Glasurit, Sikkens, and Spies-Hecker.

·  A good repaint is not cheap. In 2002, you could expect to pay $8,000-$10,000 USD for a straightforward, high quality repaint. Add bodywork or the labor to strip the car and the price can be double.


Spares to Keep in the Car
Because spare parts are generally not readily available, the following should be considered a minimum spare parts cache to be kept either in the trunk or in the garage:

·  One of each accessory belt

·  An oil filter

·  Komfort hydraulic fluid (for the 600)

·  One each front and rear airbag


Differences Between First and Second Generation 600s
There are essentially two “generations” of 600 cars: 1964 to 1968, and 1969 to 1981 (to 1972 in the US). In gross generalities, the first generation 600 cars are more elegant, and the second generation cars are more reliable.

The first generation cars have more wood inside the car, specifically under each door armrest and covering the instrument pod. The side mirrors are smaller, and the air conditioning system has front and rear components. The later cars abandoned this complex system in favor of a second “booster” fan for the rear AC outlets. Finally, the hydraulic-assist door closing system on the first generation cars was abandoned in 1969 for reliability reasons.

From a value standpoint, if comparing two identical cars from each generation, the earlier car will be worth more. However, finding two such cars is probably impossible. Factors such as color combination, condition, and mileage have a greater impact on value.