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FCP Euro Service Kits

FCP Euro Kits

Just why is it that when the job is almost done more goes wrong. Well, that’s life when you are
working on a 1975 that sat for years in the desert—things disintegrate.

I truly was excited to do one final check of the 1975 Mercedes 450SL in preparation of starting it next week after nearly a decade of silence. This moment however will have to wait just a bit longer with the discovery of a failed ignition switch. While getting ready to move the car, I realized the key felt quite sloppy as I turned it to unlock the steering wheel. With the battery still disconnected I
cranked the key through the various positions and on to the start position. The result was rather
unfortunate, nothing sprung back nothing clicked, just smooth sailing back and forth. Well, that’s
life.

Should you be the proud owner of such an ignition switch, fear not, it is not the end of life as we
know it. It does require however a bit of TLC and about an hour of your time. First step in getting this show on the road is to remove the steering wheel. To do this, carefully remove the center emblem with a plastic trim removal tool.

Now remove the nut holding the steering wheel in place. You will need a breaker bar, an
extension and a 22mm socket.


Once the wheel is removed your next step will be to remove the instrument cluster. This is easily
done by reaching up from under the dash (above the peddles) and pressing the cluster toward
you. NOTE: To do this, the under dash panel will need to be removed for access. See my article
on brake booster removal for instruction on how to remove the lower dash panel.The cluster is
held in place by a “pressure” fit, so no screws etc. to remove. There is a ribbed rubber gasket
that is surrounding the cluster that creates the snug fit. This gasket as you will discover, has
more than likely become very dry and brittle and will no longer serve to securely retain the
cluster. More on that in a later post on interior restoration.

With the cluster now released form the dash, it will only be possible to pull the assembly out just
enough to get you hand in between the dash and the cluster to unplug the four connectors. The
wires that must be detached are a lighting wire, speedometer cable, oil pressure cable and the
pin connector for the other various functions.

When all the plugs have been removed, the cluster will now be free to remove.

At this stage you have full access to the ignition switch. There are two ways to go about
replacing the switch and I will cover what I believe to be the easier of the two. I prefer not to
remove the lock assembly but rather leave everything in place and simply unscrew the switch
using a stubby flathead screwdriver. Prior to removing the screws however, remove the plug as
shown. It should also be noted that removing the ignition switch as I am proposing requires
working backwards for the removal and installation of the three set screws.


Should your ignition switch have self-disassembled as mine did you may end up with this when you attempt to pull the plug (below).

Once the three screws have been removed, the old ignition switch will slip out of the socket and
you are able to reverse the process with installation of the new unit. The screws retaining the
switch do not need to be super tight but should be good and snug to prevent loosing with
vibration over time.

With the new switch in place and secured, simply plug in your connector and you are finished.
Before reinstalling the cluster, test the ignition switch (only if battery is disconnected) to make
sure it rotates as called for. If you attempt to test the ignition switch with the battery connected
oil will begin to squirt from the oil pressure line you disconnect from the back of the cluster.

POTENTIAL PARTS NEEDED:
Mercedes 450SL Ignition Switch

Shop Mercedes Benz Parts Online Catalog Lifetime Warranty


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Written by :
West Kenyon

West Kenyon is a Multi-Media Design Consultant and automotive enthusiast. Cars in his collection include a 1956 Austin FX3-D, better known as a London Taxi, a 1965 Rolls-Royce Phantom V, and a 1975 450SL and 1981 240D by none other than Mercedes-Benz. West said, “owning one or a number of vintage cars is often an expensive proposition", which is why he does the majority of mechanical and interior work/restoration himself. West added, “not only does it save a significant amount of money to do the work yourself, it also provides full opportunity to know the job is being done with excellence and allows for an unprecedented appreciation and knowledge of the car.” For FCPEuro, West will focus on providing in-depth information on both the Mercedes-Benz R107, 450SL, D-Jetronic version and the W123, 240D. Glücklich Autofahren! (Happy Motoring)


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