Will it retract when you put slight pressure on the mast?
Clean the mast with a DRY cloth to remove road grime. If
you are mechanically inclined and don't want to spend money
on a new antenna assembly, remove the assembly from the
vehicle, remove the cover, and clean the clutch mechanism
with a greaseless cleaner like break cleaner to remove the
oily film from the brass disc ONLY.
Run the antenna through its cycle a few times as you
are cleaning the clutch. This removes the material that
causes the clutch to prematurely slip before the mast is
fully retracted. If you need to, you can disassemble the
clutch entirely and clean it. If the mast is straight and
smooth this procedure should help, unless there is a more
complex problem with the motor/drive. Good luck!
Replacing the Antenna Mast
Two techniques are listed here with the second being
most likely the easiest
you will find, most power antenna problems are related to
the antenna mast. Either the plastic has broken, or the
teeth are stripped.
An easy way to check to see if the power antenna motor
is still working is to listen when the car is being turned
off. If the radio was on and you don't hear the power antenna
motor, then the problem may be in the motor itself. If you
can hear the motor, then you probably have a mast problem.
My mast was halfway deployed and wouldn't raise or lower.
I could hear the motor working, so I bought a mast off of
eBay for $18.99 shipped.
You should also know before you start that if the seal
between your car body and the antenna isn't recently new,
then it will probably get damaged during this process. The
good news is that the retail price of the seal (at my Mercedes
dealership) is only $2.11 and is part# 126-827-14-98.
If your mast is deployed any further than the top picture
here, then you may have a problem removing the antenna from
inside the trunk.
Start off by removing the antenna from inside the trunk.
Pull back the carpet to expose the power antenna control
It's secured by one screw down low, the antenna lead,
grounding screw and control wires up top. Remove the lower
screw and slide the unit out.
Remove the grounding screw, unscrew the antenna lead
and detach the control wires. That should make the power
antenna unit completely disconnected from the vehicle.
The next step is to open up the control unit. There are
several tabs (14) along the sides of the control unit. Using
a slotted screwdriver, press down into the tabs and loosen
Loosen the two on the straight end last. The cover should
pop right off.
Inspect the inside of the control unit for any obvious
problems. I've heard that the drive belt can break, although
I've never seen that. If it has broken, that could certainly
be causing your problem.
It may be easier to remove the mast if you remove the
two screws and the plastic cover along the rounded edge
of the control unit. This is where the mast meets the teeth
of the drive unit.
I understand that earlier units may not have teeth at
I didn't take any pictures while removing the mast and
installing a new one. You can turn the drive belt by hand
to aid in the mast removal and installation.
You may be able to connect the control wires and let
the motor pull the mast back in, but I wasn't so bold. Once
the mast is in, installation is the reverse of these instructions.
new antenna mast ready to take its place in the Mercedes.
A broken antenna mast has no business on a Mercedes!
Hopefully your radio works the antenna like it is supposed
You don't need to remove the power cover but I did to
show you the guts. Pretty ingenious how it works.
The original antenna plastic cord is smooth, but I opted
for the upgraded and better toothed cable. The friction
roller is knurled and works great if kept clean.
If you have any plastic shavings in the housing, vacuum
or blow them out before installing the new mast.
With the radio off take some pliers and unscrew the antenna
and pull it up until you expose about this much of the shaft.
Then have your friend turn the radio on and gently pull
it out as the motor feeds the cable out.
Take the new mast and insert the cable into the hole
with the toothed notches facing the front of the car and
push it all the way in until it stops. Then have your friend
turn the radio off and the motor will grab the cable and
suck it in. Gently guide the mast down and tighten the antenna
back and your done.
Not having a friend helping as I didn't, requires you
to turn the radio on and run back to the antenna and try
to guide it in.
I did this several times until the cable grabbed correctly.
If I had a helper, then I could have focused all my attention
on the cable and not trying to dodge the jack stands on
Use the old antenna as a fishing pole or just throw it
away like I did.
New mast ready for another 20 years of service.
Yes those 4 jack stands were my obstacle course. It would
have been easier for me to have just moved them but then
that would just be the easy way out!!!...
Good luck... Enjoy!
SAVE BIG $$$$$$ IN REPAIR AND MAINTENANCE