I need to replace my antenna mast (motor works fine). It looks like there are two available for my car-- she's a 1980 300TD-- one is "smooth", the other "toothed" Another post linked to a great 2 for $14 deal on eBay which is right in my price range. It looks like these are only the smooth ones though, so my question is... Will this work for my car? And what's the difference between smooth and toothed anyway? I haven't yet taken the thing apart to know if it's self explanitory or not.

Thanks in advance,
Christine

One way to know for sure... Remove the liner in the trunk, remove the antenna, pop of the cover and have a look inside.

Have you un-screwed the mast and removed it to have a look?

The difference is obvious.

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AJ

1985 300D (SOLD)

In the time it took you to post this thread, you could have removed the mast and answered your own question. If the new mast has a longer nylon cable then you must open the motor assembly and remove the broken piece within. Or the new mast wont fully retract.

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.

Well I ordered a toothed one on ebay (actually my first fix) and I took out the old one and it looked smooth. I put in the toothed one anyway and it works fine, still after about a year, but it just makes this awful noise like the motor is trying to pull in more antenna than is available. My guess is it just tore off those teeth the first time, that's why it hasn't worn out the motor.

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Get the toothed, IIRC it works for both types

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Yup. It's smooth.
Thanks for all the replies. I'm going to order the new one now.

You probably just have play in your worm gear bushings and the worm gear is not "meshing" properly with the big gear.

Remove the antenna from the car and pop the case open. Remoe the 2 screws holding the motor in and turn it over. Remove the 2 little snap in bushing retainers and inspect the bushings on the ends of the worm gear shaft. If they are cracked, broken to pieces or missing you can use some vacuum tubing as a replacement. This will keep the worm gear shaft in the proper position and cure the problem you describe above.

If this goes on for too long... Eventually you will wear the teeth off of the worm gear and or the big gear.

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AJ

1985 300D (SOLD)

Well, how long is too long? It's been this way for about a year with no change. And I took out a smooth one, so how is the toothed one working at all?

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1983 240D 3.0T 4-speed manual, now sold

1989 Subaru GL Wagon 5-speed Touring Edition

Those little gears are pretty tough. If you did not break any teeth off, it should still work. Those gears mesh pretty tight when the bushings are in there the way they are supposed to be.

The only way to really tell is to open the thing up and look at it.

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AJ

1985 300D (SOLD)

In a 240D I was trying to put in the toothed one and it would not work. The original was smooth. Is the toothed one supposed to work or should I buy a smooth one.

If yours "uses the smooth type", either one will work.

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AJ

1985 300D (SOLD)

What's the trick. The smooth type works on it (240D) and was originally there. With the smooth one which is slightly bent, the mast is pulled in, but will not go up and down once it's in.

I tried about 63 times with the new one: teeth facing one way, the other way, sideways. It would go in if I force it in, but then it would not go up and down.