Power Antenna Fix
03-14-2009, 07:10 PM
#1
Member
Thread Starter
Power Antenna Fix
My 92 300E had power antenna problems. It was stuck partway up, and would not budge, even though I could hear the antenna motor running when turning the radio on and off. Although the antenna is no too big of a deal, it sure is nice to have everything functional on our cars, right?
I think the most common problem is that these antennas start sticking and then an internal plastic gear breaks. There is a good write-up here (http://www.davebarnhart.com/mb300e/antenna.htm) that describes antenna removal and gear replacement. But I actually repaired mine without purchasing any new parts, so a zero cost fix.
First problem was that my antenna mast was nearly frozen and would not extend or contract after I removed it from the car. After about and hour of use of force and liberal application of WD40, I got the antenna mast to unfreeze and extend and contract very nicely. You can buy a new one for less than $20 on ebay, but they are not probably as good of quality as the original, so was glad to see mine was workable after a bit of effort.
Second problem is that an internal gear was broken. You can get a new set of gears from the supplier in the link above for about $40, or you can buy them on ebay for about $25 (same gear, better price). Apparently these gears are the weakness of the Hirschmann drive, and a plastic part snaps before anything else in the drive is damaged. Since I am cheap, I tried to do a fix myself. First I used an epoxy - broke immediately, so don't even waste your time - too much force is applied. Then I got a better idea - used a screw to secure the tab to the gear (see pic). If you can find a small screw about the right size, this seems to be a very good fix. The head of the screw needs to be short, as there is little clearance between the gear and another piece - I actually used a different screw than the one in the pic (then forgot to take another picture) - even with a shorter head screw, I had to file down the head to get it to not interfere as it rotates.
Put everything back together and it worked great. It's now been a few weeks, and it is still working perfectly!
I think the most common problem is that these antennas start sticking and then an internal plastic gear breaks. There is a good write-up here (http://www.davebarnhart.com/mb300e/antenna.htm) that describes antenna removal and gear replacement. But I actually repaired mine without purchasing any new parts, so a zero cost fix.
First problem was that my antenna mast was nearly frozen and would not extend or contract after I removed it from the car. After about and hour of use of force and liberal application of WD40, I got the antenna mast to unfreeze and extend and contract very nicely. You can buy a new one for less than $20 on ebay, but they are not probably as good of quality as the original, so was glad to see mine was workable after a bit of effort.
Second problem is that an internal gear was broken. You can get a new set of gears from the supplier in the link above for about $40, or you can buy them on ebay for about $25 (same gear, better price). Apparently these gears are the weakness of the Hirschmann drive, and a plastic part snaps before anything else in the drive is damaged. Since I am cheap, I tried to do a fix myself. First I used an epoxy - broke immediately, so don't even waste your time - too much force is applied. Then I got a better idea - used a screw to secure the tab to the gear (see pic). If you can find a small screw about the right size, this seems to be a very good fix. The head of the screw needs to be short, as there is little clearance between the gear and another piece - I actually used a different screw than the one in the pic (then forgot to take another picture) - even with a shorter head screw, I had to file down the head to get it to not interfere as it rotates.
Put everything back together and it worked great. It's now been a few weeks, and it is still working perfectly!
03-14-2009, 10:11 PM
#3
Member
Thread Starter
No, a new mast can be had for $20 on ebay, but I am guessing that it is less than OEM quality. The Hirschmann original mast is about $75 when I looked. Keep in mind that the mast is the metal antenna part and the plastic tail that feeds into the control unit. The drive/control unit is much more expensive, but looks to be quite repairable if that is the problem. If you hear the motor running, then it is probably the plastic gear that I described above.
03-15-2009, 01:44 PM
#6
MBWorld Fanatic!
