Buy a spare to carry in your trunk! FITS THE FOLLOWING: Late 107 and 116, 123, 126 up through 1991 and 201 and 124 chassis to through 1989. ALSO FITS 1990-1993 300D 2.5 AND 92-93 190E 2.6 ONLY! The only time in my life when I have been stranded on the freeway with a dead car was when the voltage regulator went out in my 1986 230E. The brushes wore down to a point where they were making enough contact to not have the dash warning light come on, but not good enough to keep the battery charged. When the voltage got low enough in the battery the ignition system shut down and the car quit dead going 70 mph. The first indication of a problem is your wipers start to slow down or the lights start to dim. And they will not start the next time you try. - can solve lots of problems included dead battery, flashing dash lights, poor performance, etc.
As these old Mercedes approach 20+ years the brushes are wearing out and the alternators are failing. Many owners are having their expensive alternators replaced without knowing that it might just be the inexpensive voltage regulator mounted on the back on the alternator. I am now taking a preventative approach with my customers and just replacing all the old voltage regulators. Includes picture installation instructions and troubleshooting tips. This small regulator is easy to install by jacking up your Benz and going underneath to the back of the alternator. This is a quality German-made aftermarket voltage regulator with improved brush material for a long life. If you have not replaced this unit in the last 5 years I would highly recommend you do...One of the best run insurance measures you can take!
Here is an example of what you will find when removing most old regulators. Look at those brushes! They are worn down to nothing. This alternator would have failed at any moment. Recommend you always carry a spare regulator in the trunk of your Benz - especially if you drive long distances away from home. PLEASE NOTE: If your voltage regulator has a rectangular-shaped housing then please see our early style replacement voltage regulator.
Sometimes it is very hard to get to the screws when the alternator is on the car as you can see below:
If yours is in a tight location recommend a right angle ratcheting screwdriver if you don't have one.
One of the handiest small tools you can have