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Replacing the antenna mast on a 83 300 DT

7K views 29 replies 5 participants last post by  cooljjay 
#1 ·
The antenna on my 83 has been broken off for quite some time, I just use a mp3 player for my tunes but recently I took the antenna mast off of the "wrecked 81 240D" and thought I would use it as a replacement on my 83. How do you feed the plastic line down inside the motor assembly? I was going to just try to fish it down the hole but since the plastic line is used it has a curved memory and I don't think I will be able to hit the spot. Is it advisable to peel back the inside trunk liner and open the motor assembly to feed the line it? Has anyone ever replaced their mast that they would be able to offer some advice? Thanks in advance, Cyberbach
 
#2 · (Edited)
Its really simple....but if the old plastic line from the old mast is broke off and a piece is stuck in the antenna, it will have to be removed by disassembling the motor. If the plastic line was still intact on the old mast. Feeding the new mast in is simple.....turn the car on, till the radio comes on.....go out to the antenna and feed the line in, till you can't push it in anymore.....go back into the car, hit the down part of the antenna switch....you'll see the motor pulling the antenna mast cable in....then screw the antenna in....all done....

Pictorial

http://dieselgiant.com/mercedes%20antenna%20mast%20install.htm
 
#3 ·
Best done with a friend! The nylon cable is curved even on a new one because it wraps around a spindle in the motor. First compare yours with the replacement. Is the nylon the same length? Is it notched on one side or semi round with no notches? You must replace a notched one with the same. Assuming the nylon is the same length, start the car, have your friend stick in the mast nylon and hold it down with his hand on the fender. Now turn the radio off. It should immediately grab the nylon cable and pull it in. If not repeat above till it grabs. Once pulled in, install retainer nut. Then power on the radio then turn it off. It should seek its proper length and fully retract. Clean mast when you wash the car. 2 reasons; verify its not bent in any way, and keeping it clean lengthens its life. I used to replace them in the service drive for my service customers telling them to simply turn the radio off, then on.
 
#5 ·
I just recently replaced the top section that connects the mast and cable (because I had no reception from my original radio) and I had a heck of a time re-installing the antenna mast. The plastic cord kept getting hung up on the way to the gripping wheel. I ended up opening the unit and lining up the the cable by hand, then letting the motor wind it in as it lay there in the trunk.
 
#6 ·
OK, thanks for all the help, the problem I was having was there WAS a small piece of the original line still stuck inside the motor unit. However, after removing the cover and the small piece, I inserted the new mast and fed the line down into the hole and turned the radio off to engage the wheel to pull the line in which it did and I was able to tighten the nut to secure the antenna. When I went back to look at the motor unit I noticed the white plastic line was sticking out of the motor assembly. Where is this line supposed to go.... just coil up inside the box, or does it feed out of the bottom of the box and just go into the trunk area? It seems like I'm not doing something right? Am I supposed to cut off the excess line after fitting it? See picture below:

 
#7 ·
The cable is suppose to wind up in a spool behind the gear in the motor.....its hard to say what the issue is with your motor with out a closer photo of where the cable is sticking out.....if you look at where the cable is sticking out, you will see a little plastic slide that guides the cable into the spool behind the gear....you will probably have to remove the motor to fix the issues.....if you can post a closer photo of where the cable is sticking out I may be able to give you a correct answer as what it may be....as it stands it could be that plastic guide is broke, there is a larger piece of cable stuck in the spool, the cable needs to be reinserted or the metal wheel that puts pressure on the cord is froze up....it could be one or a combo of these...
 
#8 ·
Remove the cable from the motor by turning on the radio after removing the retainer nut from the mast and as its extending pull gently on it to remove. NOW, reinstall the motor's cover. Then, reinstall the mast with a friends help. The nylon wraps up on a spindle within the motor.
 
#9 ·
OK, here's another picture of the motor assembly with the cable sticking out. It almost appears as if the white plastic piece is directing the cable out of the assembly as opposed to guiding it behind the drive wheel. Directly behind the drive wheel there appears to be a drive gear, is the reservoir area behind THAT?


 
#10 ·
I'm thinking about removing the entire motor assembly from the wrecked 81 240D that I took the mast from.... how is it attached? I see the Phillips head screw that attaches the assembly to the car frame, is this the only screw besides the mast assembly at the fender?
 
#11 · (Edited)
It looks like your little metal roller wheel is froze, lots of gunk there.....you can free it up and oil it with 3in1 oil....I did that with mine at first but then not long ago, I completely disassembled the whole motor and use brake cleaner to clean all the old grease and built up gunk out of the motor......that little guide directs the cable behind that gear into the reserve....if you look closely you will see the little hole it goes through into the reserve.....simply pull the cable back out, and refeed it in, paying attention it feeds through the hole.....

Antenna is simple to remove, remove the Phillips screw and then the collar nut where the mast goes through the body...

Many of these antennas don't work, with out full disassemble and cleaning....so chances are your other one may be in the same shape...
 
#13 ·
OK, I figured out how to get the old assembly out of the donor car, had to remove a bunch of sun roof assembly, and once I removed it I noticed something different about the white plastic guide at the bottom that is supposed to feed the line onto the spool. Here's the donor assembly (which works last time I tried it).




And here is a close up of the unit that is in my car. I am having a hard time getting the right angle for the pic as I have a big base speaker cabinet in the trunk that really cramps the area I'm trying to expose to take the picture. But I think you can see the white guide is broken and it looks like there is still some line stuck inside. I was thinking if I could get a needle nose on the end of the line I might be able to pull the remaining line out then feed the new line in through the hole.

 
#15 ·
hey carnut, when I bought this car it had a broken antenna. I bought a new mast some time ago, but I've been using an ipod with the auxiliary in port for tunes and have just blown off the radio. When I was tarping my 81 for the winter, I removed the antenna mast so the cover would fit better. Once I had the mast removed, it inspired me to go ahead and replace the broken one in my car. Since the old antenna was missing I just figured like you said, to simply insert the replacement mast and turn the radio off to pull the line in.... but it wouldn't work. Evidently, the previous owner had encountered problems with it and never addressed the repair leaving to me to try to figure out what had happened. Now I have. Thanks for the help
 
#16 ·
Thank you. My recently acquired 300SE also had a slightly bent mast when I bought it. Wouldn't fully retract or extend. I removed it, cleaned and straightened it and reinstalled it. I do wash the mast every 2 weeks or so, and inspect for any bent sections. I also have 3 replacement masts in the tool box!!
 
#17 ·
Put the antenna assemble from the 240d into the 300d........the antenna motor in the bottom picture is garbage, because as you see the antenna cable slide at the bottom is broken.....no matter what you do, the cable will always not wind correctly.....and you can also see the old cable is stuck in it.....just install the 240d motor and mast....,you should be fine.....
 
#18 ·
... and that's what makes you so cool J, you read my mind! :) Gunna take the entire assembly down to my jewelry store tomorrow to ultrasonic the mechanism, clean it up and re lube it. After I figured out how easily the unit goes in and out it would seem to be a no brainer to take the easy road and replace with the one from the donor car. Easy peasy.
 
#19 · (Edited)
No problem, I don't know if I would sink it in an ultra sonic cleaner.....take the old one apart and you will see there is very little to the mechanism....I didn't take that large nut off that you can see in the last photos you posted because I wasn't sure of the torque specs on it......if you remove the Phillips screws you can see the entire mechanism comes put of the housing, then on the rear you will see the holder for the cable and a pin that can be removed to take it off for cleaning.....the metal wheel also comes out for cleaning.....you have to be careful not to get grease or oil on the cable or toothed gear as it won't grip.....I greased the small metal wheel and used 3in1 oil on the rest of the moving parts.....take the old one apart first to see how it works.....I just worry the ultrasonic may damage something or the already died out plastic pieces....oh and the mast housing unscrews once you remove the set screw on it....
 
#20 ·
Thanks again cool, yea I wasn't planning on dunking the whole assembly but mainly removing the tensioner wheel and clean'n the gunk off around the spring. I have a high pressure steam generator that works great on stuff like this, then re lube with synthetic grease,
 
#22 ·
******** UPDATE ************

Well, I took both antenna units out of the vehicles and combined them to make one good unit, re-installed the "Franken-antenna" and fed the plastic end of the mast in and everything worked great. The antenna didn't extend as far as I would have liked but it was working fine and I could extend the antenna further up with the switch on the dash. I should mention that I had spliced into the power lead for the antenna to feed my amplifier in the trunk and I re-hooked that up as well. I've been using it this way for about a week or so and last night when I went to park the car and lower the antenna prior to exiting the car, suddenly the antenna stopped working and I lost the amplifier. I went into the house thinking surely I popped a fuse but today when I checked the panel it indicated the power antenna was fuse #2 that also controls the trunk light and the fuse is fine, I still have a light in my trunk but no power going to the antenna or my amplifier. I will go back into the trunk to look things over but does anyone have any idea if there is another in line fuse or anything that would cause this power loss? Thanks again, Cyberbach
 
#23 ·
OK, I went back in the trunk and unplugged the antenna and plugged in the other unit, turned the stereo on ... and nothing. I'm no longer getting power to the unit and yet my trunk light continues to work that shares fuse #2 with the power antenna. Does anyone know if the power runs through the dash switch that controls antenna height? I was messing with the switches when the unit failed.
 
#24 ·
I'm no longer getting power to the unit <snip>

Does anyone know if the power runs through the dash switch that controls antenna height? I was messing with the switches when the unit failed.
Yes it does. It provides power from the radio to the antenna motor relay when the switch is in "Auto" (middle position) or "Max" (up position). Sounds like you may have inadvertently disconnected the antenna switch, or did something to the switch to break the circuit.

Also check that you are getting power from the radio to the antenna switch.
 
#26 ·
I took the antenna switch out of the dash, opened it up and examined it, it was fine, reassembled it and re-installed... still no change, no power. I still have my radio, just not my rear speakers as they were feeding off of the amp that is no longer receiving power as it is pig tailed into the harness that feeds the antenna unit. If there is no other fuse in the antenna unit other than the front engine bay panel, then I have to have a failure in the harness somewhere.
 
#28 ·
If fuse #2 which controls the remote antenna was blown or corroded then EVERYTHING on the circuit would quit functioning as well as the antenna correct? I still have my trunk light which is supposedly on the same circuit and so I didn't try to replace the fuse. The ones I have in my panel are the ceramic style bullet but they appear to have lead strips on the sides... are the copper ones better? Where did you find them? I just looked at autohaus and all they show are the original style. Do you get them from the dealer?
 
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