Antenna Mast Plastic string replacement

[ajmcforester]

I have an original antenna mast with the plastic string broken, and about 10 motor units that all now work. I was wondering if anyone has tried to replace the plastic string?

I have an idea I would want to try however I only have one mast, not even a later model one to try first, so I wanted to see what has been tried. If you tried something please let us know even if it failed.

Hear is what I was thinking of doing.

I was looking at string trimmers' string at the same diameter and stiffness to replace the string. The nice thing about trimmer string is it comes in different harnesses, and thicknesses so finding what will work will not be the problem.

The problems are getting the old string out of the mast and attaching the new string, or even splicing the old string to the new string. I don't have one that I could brake and see how the string is attached or how the tip of the antenna is attached. Does anyone know how the antenna tip is attached? If I could get it off I think I could take the antenna mast apart.

If I can't fully replace it I might try to splice it, by crimping a metal piece end to end. The only problem is it needs to be very strong, and thin to last so I don't think this would last long that's why I don't like this idea so much.

WHat are your thoughts and ideas?

Edited May 27, 2011 by ajmcforester

[esprist]

I have been thingking about that, too. I have been saving those old mast, but so far no success.....

[Willoughby Z]

In the same boat here- good motor unit, broken 'string'/mast. Some punk broke mine off while it was parked at night out in public, stupid me for leaving it extended. Can't say how the plastic is attached in the upper section, probably doesn't matter, I think it would impossible to repair the mast sections.

I have disassembled mine and found that there is a small metal ferrule with a very small screw that acts a keeper that fits into a slot in the wheel. It'll make more sense when you take it apart, which isn't hard to do, just lots of parts so keep track of order/orientation. Trimmer string sounds like a great idea, the ferrule could re-used, even if it's a micro-surgery process. I'm not sure about grafting or splicing the plastic rods together, there are pastic welding tools around, not sure if it's an appropriate solution.

My problem was findind an undamaged sectional mast and how to remove the lower mast section from the main body, even if I could find one. I did order and receive one (actually two, one as a back-up) from AntennaX that was supposed to work for several years of Zs but it was only similar. The plastic 'string' was not smooth but had teeth and was a different diameter. So I returned them.

For the moment, I have a short, black rubber, fixed aftermarket unit in place until I find the good mast/bad motor unicorn to marry with my broken mast/good motor unit.

[conedodger]

I have done it. It was years ago but let me try to recall... I had a broken mast. I bought a new mast from Nissan as they were available then. I extended the mast completely and inserted the plastic gear line into the motor. I applied 12 volts to the motor and it spit it out. I reversed my connection and did it again and it reeled it in. Success. Not too hard.

[Arne]

Seems to me that the original strings from the 240Z mast was attached to the spool reel at the end with a cotter pin or something similar. I had to pull the reel cover off to get the broken end out.

Like others, I only had my one original mast to work with, and I could not figure out how to release the old, brittle string from the base of the mast. I eventually gave up trying, for fear of damaging it. Since my original string was broken fairly close to the far end, I took the metal barb off the broken end and and reattached it to the remains of the string on the mast. As such. my original antenna is now about 8" shorter than it was when fully extended.

I'd love to replace the string though, if anyone figures out how.

[JLPurcell]

Seems to me that the original strings from the 240Z mast was attached to the spool reel at the end with a cotter pin or something similar. I had to pull the reel cover off to get the broken end out.

Arne, As my memory serves me your are correct. The end of the nylon string was attached by a "mini" clip. The mast replacement was easy but it did require that you open remove the interior panel and the reel cover to remove the pin. I have never heard of anyone being able to just replace the nylon string. jlp

[ajmcforester]

Detaching the spring from the spool is the easy part the hard part is detaching the mast from the plastic string. I got brave just now and grabbed to rags and two vice grips and see if the tip of the antenna mast would twist off, and it did. It is threaded on after the tip came off it slid right out, now I know what I have to work with. I took pictures.

They stamped it on with 8 small points. I was thinking using heat and burn off all the plastic. Then soften the plastic to insert the new plastic string. What are your all thoughts?

[JLPurcell]

I believe with today’s new glues that you might be able to just glue it in place. If not I think I would try removing the old string rounding out the interior, glue the new string in place then drill a small hole through the shaft and string, glue a small rod through the hole and then when the glue dries file off the rod even with the outside diameter of the shaft. That would definitely hold over time and use. jlp

[Arne]

OK, that looks encouraging. Keep us posted on your progress.

[ajmcforester]

Will do I'm going to look for string.

[FastWoman]

Yeah, if it will burn out, burn it out. Then you'll have 8 dimples inside. Roughen up the end of the new string with very coarse sandpaper. Then put some gorilla glue in the hole, dampen the end of the string, insert, and let cure. Then trim the excess. That gorilla glue (dense polyurethane foam) is incredibly tough stuff. Another great adhesive is 5200 adhesive/caulk -- the regular stuff, not the fast cure. It's another polyrethane product. Give it about a week to cure.

[Arne]

Does anyone know just how long the replacement string should be? I didn't have enough foresight to keep the broken piece from mine so that I could have measured the proper length. I *THINK* the broken part was 8", but can't be 100% certain 5 years later.