Old Antenna Mast won't release

[PCM84]

I'm trying to replace the antenna mast on my 560SL... theoretically the antenna should "want" to come up and out as soon as I've released the small nut at the top... but that doesn't seem to be happening: the mast seems as firmly attached as ever.

Any thoughts?

[cbdo]

I'll assume you haven't done this before; forgive me if it's more basic than you need.
If you're trying to do this with the antenna in place as the directions on the replacement mast packaging describe, it may hang up. If you can, it may be time to execute Plan B, which is to remove the antenna from the car.
Check this site on antenna mast replacement:
http://www.geocities.com/rotospud/mercedes/replacing_the_antenna_mast.html Follow the procedure shown to get the antenna out (it's really pretty simple). If you're gentle, the rubber bushing that holds the antenna on the body surface shouldn't be damaged at all.
Once it's out, the best move to release the cover latches is with the case lying flat, cover side up. The hooks from the cover pass under a rim on the case. Use a screwdriver blade placed on *top* of the rim to (fairly) gently pry each hook up away from that rim; it may not look like the right move but it is.
Removing the cover slowly and gently, note the three black rubber bushings on the retaining posts, sitting between the cover and the case (they're visible in the last photo on the linked site above).
Once you've got the cover off, remove the white plastic guide with the two small Philips screws. Take it off slowly, as there's a metal roller and axle that it holds in place. Remove these.
Turn the belt drive pulley to rotate the gear and start extending the antenna. You'll notice the top gear turns but the one below it may not until you've gone nearly a full revolution (it's part of the clutch system for this to happen, and it's why the antenna motor runs a second or two before the antenna starts moving). While you're doing this, check the gears for any stripped teeth; usually it's the antenna core, not the gears, that strips, but not always. Once the antenna is perhaps halfway out, you'll be able (if you're getting impatient) to unscrew the collar at the bushing, lift the white plastic antenna core disengaging it from the gears, and pull the rest of the core out of the housing. Rotate the antenna and core to keep the teeth on the core from engaging the gear, and you can slide the whole thing out gently.
Installing the new mast is simply a reversal of the removal procedure. To start, get the new core threaded and engaged on the gear, then replace the roller, axle, and white plastic guide/cover; this is necessary to get the core feeding into its housing correctly.
I know because I just finished doing it for the first time about two hours ago!

[PCM84]

Somehow the small white plastic ring at the base of the old antenna had gotten flattened enough so that it would slide out the top of the antenna housing... so after opening the antenna and following your (very good) instructions... I was able to free the antenna mast and pull of that small collar... works like a charm now....

though I will have to get a new grommet that goes through the body of the car... this was in three pieces!

Thanks

[cbdo]

Dad drove Benzes for almost twenty years, and I remember antenna problems off and on through all of them. Now that it's been fifteen since his last one, I finally know how to solve it for about twenty bucks and a half-hour's time! Too soon old and too late smart...