Hi,
As a semi-novice, willing to experiment with replacing some parts, I was wondering about the complexity of replacing the power antenna mast on a 1990 560 SEL.

Although the mast does not appear to be bent, it does not extend all the way up. I am assuming it it just the mast that is the problem. Can just the mast be replaced, and if so, is it an easy replacement? If its just the mast that is the problem, can the mast be easily removed from the antenna assembly, or does the entire unit have to be replaced?

Thanks for any help,
Ron

First Ron, when you say it won't go all the way up, just how far does it go? If you're talking about less than a foot, that's one type of problem, if it goes higher than a foot, but doesn't seem to go up as far as you think it should, that's another. Also, is this a recent problem, has it just gotten worse over time, or has it always done this?

While the mast is a separate part, and can be replaced, that may not be what you need to do to solve your problem. I would start by thoroughly cleaning the mast with common cigarette lighter fluid, or penetrating oil. Put some on a rag, have someone else extend and retract the antenna while you gently wipe down the entire length and see if it extends further after cleaning. If this solves the problem, ad some lubricant to keep it moving smoothly, and you're done.

Other things you can try if this first one fails:

Is there an antenna switch on your dash? in my car, you can turn off the antenna completely, or extend it further with this switch. The antenna extends to a preset length when the radio is turned on, and if you need more signal strength, you use the dash-mounted button.

Finally, you may need to remove the mast, and open up the motor to see if there is anything (like leftover pieces of a previous mast) in the gearbox that drives the mechanism. First loosen the nut at the base of the antenna mounting where it protrudes from the car, then have someone turn on the radio to extend the mast, and carefully pull on the mast until you have removed it. You will start to see a white(?) plastic "cable" that has gear teeth on one side of it. It is important that you keep track of whether those teeth point towards the front or rear of your car.

Once you have removed the mast, you can go into the trunk, and remove the motor, take the cover off, and look for obstructions in the gear pathway. If you screwed up and didn't keep track of the direction of the gear teeth, you can look at the way the lead for the mast feeds into the motor, and you will know what way it needs to point on reinstall.

To reinstall, you obviously replace the cover on the motor, and bolt the motor back in where you got it from. Then, making sure the power leads and antenna wire are connected, turn the radio on, so the motor moves into the "extend" position, and making sure you have those gear teeth pointed in the right direction so they will mesh with the gears in the motor, push the antenna lead into the antenna hole as far as it will go, then have someone turn the radio off, while you keep pressure on the lead. The motor gears should grab the teeth on the antenna lead, and pull it into the housing.

There's also lots of additional information in the archives that you can access by using the "search" button at the top of every page.

Good luck, and let us know what worked for you...

__________________

Scott Longston
Northern California Wine Country...
"Turbos whistle, grapes wine..."

...with M-B antennae, especially for your car's body style. Everything that Scott wrote is good, sound advice.

I'd only add the following two caveats:

1. Be sure that you use the right kind of lube for the antenna mast and that you only apply a small amount. Use of the wrong kind of lube, or too much lube, can gum up the works and will eventually cause you to buy a new antenna mast and/or motor. I think that Hirschmann sells a lube pad just for their antennae.

2. I'd also suggest that you stand by the antenna and listen while someone turns the radio on and off. If the antenna stops moving but you can still hear the antenna motor whirring, then you probably need to replace only the mast.

The mast itself should not cost more than $30 - $35 and, as Scott pointed out, it is very simply to replace.

Good luck.

__________________
Current Benzes

1989 300TE "Alice"
1990 300CE "Sam Spade"
1991 300CE "Beowulf" RIP (06.1991 - 10.10.2007)
1998 E320 "Orson"
2002 C320 Wagon "Molly Fox"

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