Tail lights: too hot to handle

The W114/W115 hit the market in 1968 as the first mid-sided Benz, later becoming the E Class we all know today. It was the year of manufacture that gave the model its other common references of Strich-Acht, /8 and Stroke 8.   

Originally only available as a sedan, a coupé variant was added to the range in 1969 which was the year UGU was built.  Her VIN# ends with the numbers 002510, so perhaps this means she was the 2,510th coupe made?

In 1973 the /8 underwent a face lift creating the series 2 which, to the untrained eye may not appear that different to the series 1.

Externally the changes included a lower and wider grille to match the styling of the larger W116 (S Class) with was introduced to the market in 1972. The /8's front double bumper was discontinued, retaining only a single bumper, and the front door quarter windows were deleted.  New mouldings were fitted to the A pillars to prevent water and dirt from the windscreen flowing around onto the side windows, and finally, with the same consideration for safety, new ribbed tail light lenses were introduced. As with the new front grille these tail lights were similar to those on the W116.

Mercedes-Benz display circa mid 1970's. Note W114 series 2 in the foreground with W116 beyond.  If you look hard, right at the back you will see a crash test W116, presumably to show the cars superior safety features.  You will also see a Citroen sign, making me believe this is a motor show display rather than a Mercedes-Benz showroom.

Image source unknown.

The idea behind this type of lens was that the ribs would prevent the entire lens from becoming obscured by road dirt and therefore making the car more visible to following traffic in poor weather.

Whilst I appreciate the advancement in safety, I personally prefer the original flat lenses with their chrome surround.  The ribbed lens is bigger than it's predecessor which meant the chrome surround was deleted.  In doing this, an element of visual bulk was added to the rear of the car which can be seen in these pictures:

 

Series 1 tail lights. Note the flat lens and chrome surround.

Image source: Mercedes-Benz W114 & W115 International forum

Series 2 tail lights. Note the new ribbed lens with no chrome.

 Image source: www.autoevolution.com

It's not often that you get to see what the tail lights of the car you drive look like at night unless someone has stolen your car and you are in hot pursuit haha.

To overcome this, I often find it useful to reverse up to a reflective surface such as a glazed shop front, so that I can do a quick check to make sure the reversing, tail and brake lights are all working. Indicators are an easy one to identify as the "clicker" and dash light flash speed increases once a bulb blows.

Not long after purchasing UGU I did a check of all the lights and everything was working, so no further inspection was done. It wasn't until my wife followed me home one evening in her car that she noticed that the drivers side light looked "weird" and different to the passenger one.  Once home I turned the lights back on and got down on my knees to look at the lights at eye level. It wasn't until I did this that it became obvious there was something wrong. The drivers side reversing light, located below the tail light, was being illuminated by the tail light above.

The next morning I opened the boot and unwound the two plastic caps that hold the lens in place allowing it to be removed exposing the inners of the lights. The problem was immediately apparent - the inside of the unit was melted and completely destroyed.

I pulled all the bulbs out and checked their wattage against the helpful stamped markings Mercedes-Benz included on the light reflector. This should stop someone installing the wrong bulb, but alas this was not the case with UGU.  All of the bulbs I removed were the correct wattage indicating that the damage had been caused by a previously installed and later removed bulb that had too high a wattage.

Warning: the following images may cause distress!

I apologise in advance and am aware it may be confusing, but the photographs below are a mixture of the left over parts which is why the melted area has no electrical component behind it.

As you can see in the pictures the reflector is extensively damaged and the division between the tail light and reversing light below is very distorted allowing the light to be emitted in both chambers.  You can also see the numbers indicating that a 5W bulb was the correct size to have been installed.

The heat from the incorrect bulb was so intense that the damage was not limited to the reflector but also melted the light lens.

There was further damage to the light reflector too, but not caused by the bulb.  Somehow someone had broken the end of the reflector off, perhaps by standing on it, but regardless of how it happened, I now had a melted and broken reflector that was destined for the bin.

I got online and started looking for a new rear light.  I sourced what I needed in Germany via Ebay, and the new light arrived a week later.  It was in great condition, the coloured lens was bright and un-faded, the chrome surround was in "as new" condition and it even came complete with bulbs!! It was like Christmas.

Removing the damaged tail light from the car is very straight forward and all done from inside the boot.  First unplug the electrical connection, then undo the four small nuts (one in each corner) remembering to keep a hand on the light as you don't want it to fall out of the car and smash on the ground.

With all the nuts removed and the electrical connection unplugged, the light will pull out from the outside.

Time for a cup of tea.

The simplest thing to have done would have been to install the new fitting in its entirety, however I noticed on the back there was a stamp stating it was produced in 1973.  To be true to UGU I decided to dismantle the 1973 light and rebuild it within the original casing.  This could not have been easier and only took an hour including cleaning of each part.

With the fitting complete it was time to reinstall it and check everything was working, which thankfully it was.  The only thing I would say to be careful of when doing this is to check you install the rubber seal carefully as you do not want water getting inside the boot through the light.

With everything working I fitted the new lens and the job was done. Easy.

I now have a few pieces left over that may be useful to someone else, such as the chrome surround and plastic housing.  I will list these in the Tyro Part Mart should anyone want to get in touch.