Electric aerial removal - dismantle?

[kelvinp]

For a long while the electric aerial on my 740 estate has been snapped off, the radio works ok without it so not been overly bothered, but it is one of the little jobs on my list of things that I want to do properly. I have bought a replacement telescopic section but despite having remove the nut I cannot pull the sleeve out - there is very little left to get a proper grip of.

Is there any easy way to dismantle to get this out - I've looked behind the D post trim and there seems to be a tube joined there?

Failing that, anyone have an estate electric aerial assembly?

Thanks

[brutusmotorsport]

you be better of changing the whole unit for a new one.

[bob12]

I went all through this a few years ago when I fitted an electric aerial to my 745.

My original mast aerial had broken and I thought why not fit an electric aerial as all the wiring is in place on the looms and behind the dash to fit the overide switch.

I had acquired several in various conditions and had taken one to pieces. My recommendation is don't take the motor drive to pieces as it's not easy to re-assemble.

You should be able to extract the aerial fairly easily once the aerial is connected to the plugs on the loom in the left hand cargo space trap door. You don't have to assemble it to the car just lay it back in the cargo space.

I assume your new aerial came with instructions including how to eject the old aerial under power (raising the aerial under normal operating conditions when you switch the head unit on). As soon as it starts to eject or before grab it with thin nosed pliers and keep pulling gently until the whole lot comes out with the plastic drive section. Note which side the drive cogs face (inwards towards the motor).

You may well find that the new aerial will not sit down properly into the exterior holder on the D post. Your new aerial should have a brass tubular fitting/insert that 'holds' the aerial in the top of the tube on the D post.

If this is the case the old brass tube is still 'stuck' in (through age) in the aerial fitment. It's very difficult to see BUT if you can't get a 10mm drill in the aerial hole it's stuck in there and, you will have to drill/ream it out with a very straight hand to that diameter. When you are nearing 10mm the drill bit is likely to grip the old brass tube and you can pull it out.

As the oft quoted by the 'Book of Fantasies' reassembly is the reverse of removal.

Bob

[kelvinp]

The problem I have, is that where it's been snapped off there is nothing to get hold of so I don't think there is much left of the original aerial. It's the section which is retained by the nut that I can't get out.

I have some thread extractors so I might have a go with them. I've tried to get some WD-40 down the sleeve so I'll see how I get on.

[bob12]

Didn't appreciate you had the electric aerial in place.

Can't quite understand why you cant grab a bit of the old aerial. At the least it's got to be level with the top. Just squish it around a bit plus lots of release oil until you can get a pair of small nose pliers to grip even a small part of it.

I would fear that if you try to remove it with a threaded extractor it will bind the hollow aerial to the tube of the permanent fitting and you won't get it to shift that way. You have to have the aerial shaft free to eject itself under the power of the drive motor.

I assume you have removed the exterior black shroud that holds the aerial fitment to the D post?

Might help understanding if you put up a pic of the top where it's snapped off.

Bob

[kelvinp]

I'll post a pic tomorrow. I'll try and use some more WD-40 and some long nose pliers when I get a bit more time.

[kelvinp]

I have done a bit more investigation today and worked out how it comes apart and got a bit further but cannot get the aerial to engage.

I've disconnected the tube that runs up the D pillar at the top section and was able to extract the broken piece of aerial - I had no flexible drive so obviously when the aerial was snapped off someone took this with it.

The brass bush I couldn't remove but I tried the new aerial and it is ok - I found the aerial had to push up from underneath (I thought the whole assembly pulled upwards)

With the radio switched on I fed the flexible drive down the rest of the tube and checking for length it goes all the way down but doesn't want to engage when I try turning the radio off - is the drive in the motor knackered?

From memory, the aerial didn't always want to retract at times so could this have been why?

[bob12]

All a little confusing.

To refresh my mind I have just been out to my garage and 'am now holding a whole assembly complete as well as the a complete D post black plastic/aluminum section that locks into the exterior body and plugs into the drive motor the other end.

The black plastic section is removable from the aluminum section with a little forces once the two securing screws are removed. At the other end the black plastic section is again fixed to the motor with two screws.

If you have taken the extended D post mast section to pieces and removed the s'steel hollow mast and not found the plastic drive that should be connected to the end of it someone must have taken it out somehow as the lot should be all joined together. If the motor was dismantled to remove the plastic drive that's a likely recipe for disaster.

If you have now tried to fit the new aerial and it won't engage with the motor there are possibly two options

1) You haven't got the plastic drive cogs on the new mast facing the right way round. As said previously the cogs must face inwards toward the motor and large capacitor to enable the motor drive to lock on to the flexible drive and kick in the motor to start to run.

2) Alternative the motor/cap/relay maybe shot!

Bob

[kelvinp]

Hi Bob, that is as far as I have got, the plastic drive was missing with the whole aerial. I've only taken the top section apart. I haven't taken the motor to bits!

There's a whirring noise from it when I turn the radio on and off, so suspect that I haven't got the drive engaged properly - it tends to coil up as I put it in. I'll double check which way the teeth face, they should face to the right as I look it?

[bob12]

Sounds(!!) like the motor is ok and hunting for the drive cogs. Right /left confusing.

Lets put it this way ...... the drive motor assembly in the well when bolted in faces inwards from the left hand/near side across the cargo space towards the right hand/off side of the car.

The cogs of the plastic drive (that wrap around the innards of the motor drive assembly) should face towards the drive motor as you poke the aerial drive down and not in any other direction (i.e. not towards the back, front or curbside of the car). If you think about it and the shape of the drive motor the cogs have to face inwards towards the circular motion of the motor.

If you still can't get it to connect my only other thought is that for some reason it might be there is still some broken off section of the plastic drive hidden within the motor casing. You can take it off to look but ..... be careful to note where everything goes.

Best of luck .... Bob