Harada Power Antenna Teardown Guidance

[Hardway]

Ever since I purchased my '71 240z the power antenna has not worked.  I pulled the hatch panel out to reveal the original single speaker a Harada model 6424 power antenna.  It does not have the bullet tip at the end of the mast but instead has a squarish cylinder.  I tried putting 12v to the wires each way and got nothing.  I had to open it up in order to manually wind the rest of the mast down so I could remove it from the car.  With it on the bench I could see how much rust it had that might have lead to its demise.  Before giving up on it I would like to dis-assemble it and possibly rebuild it.  I was hoping to find a guide that ilustrated this as it seems very easy that something could go flying across the garage if I am not prepared for it.  I could not find any guides or posts that discussed taking one apart.  I looked around on Google and can find other teardown guides for vintage Cadillac, Mercedes, and Volvo antennas but not this one.  I did find the post below of Jerry Purcell's re-assembly of an original antenna but the clutch mechanism on his looks slightly different than mine.  Based on this and the absence of the bullet tip, I believe mine might be some sort of replacement.  My car is a 8/70 build, #8011.  Any help is greatly appreciated.

http://www.classiczcars.com/forums/topic/46443-antenna-rebuild-restore/

 

Edited September 4, 2016 by Hardway

[Patcon]

Maybe the mast is a replacement but the rest is original???

[Namerow]

I successfully rebuilt the Harada antenna from from my 5/70 Z about a year ago, using Mr. Purcell's excellent write-up as a guide.  My antenna does have the bullet tip.  In addition, the motor housing 'can' does not have a model number stamping.  Instead, it wears an embossed, circular mftr's plate (same as Purcell's, IIRC).  Maybe we have an 'antenna expert' in this club who knows if/when Nissan switched to an updated Harada antenna (which I assume yours to be).

I don't know whether your unit has had a non-Harada mast substituted or not.  I kind of doubt it, because I think it would be a difficult swap (the nylon drive 'rope' is attached to the base of the center section of the mast in a fairly permanent way, IIRC).  On the other hand, maybe these things all used a generic mast design, regardless of mftr.

I can tell you that the disassembly/re-assembly of the clutch is pretty straightforward and there's nothing spring-loaded that's going to explode out of the casing.  The main thing to observe during disassembly is how the (black) plastic 'guideshoe' pieces for the nylon 'rope' fit into the casing.  I've got lots of pictures stored away if you get lost.

BTW, as you explore the innards, you'll find out why the outer casing rusts.  There's a rather poorly designed drain in one of those guideshoes that's supposed to give an exit path for water that weeps down the chrome mast.  It probably clogged after about Month 3 of use in most Z's.

Edited September 4, 2016 by Namerow
typos

[Mikes Z car]

I wonder if 12V is supposed to be supplied between one of the wires and the antenna motor case ground?  Each wire then would make the antenna reverse direction?  In 2008 my 70/240Z came with a radio shack retractable antenna that I installed and it works fine but I have an aftermarket radio, not sure the antenna I have would work with the original switch even if one of those old radio shack auto antennas could be found.  I have wondered about the idea of gluing a small antenna wire to the back hatch glass at the top.

[sweatybetty]

if i have to take something apart that may have parts that go flying, i put it inside of a 1 gallon zip-lock bag. the bags are easy enough to see through, and will keep the parts from flying.

[jfa.series1]

13 hours ago, Mikes Z car said:

I wonder if 12V is supposed to be supplied between one of the wires and the antenna motor case ground?  Each wire then would make the antenna reverse direction?  In 2008 my 70/240Z came with a radio shack retractable antenna that I installed and it works fine but I have an aftermarket radio, not sure the antenna I have would work with the original switch even if one of those old radio shack auto antennas could be found.  I have wondered about the idea of gluing a small antenna wire to the back hatch glass at the top.

Yep, the motor is self-grounding thru the case and the attached bracket at the bottom that bolts to the body with a wingnut.  The two power leads are for the up/down action of the motor.  The motor can easily be tested out of the case with a ground wire clipped to the frame and power applied to each lead.  I have a spare Harada motor in excellent working order if one is needed.

[Hardway]

Thanks for all the info guys.  Good idea on using a 1 gallon Ziploc bag Sweaty!  I am hoping to work on the antenna some more this week as I am currently putting struts on my '99 Camry this weekend.  I will post more updates soon!

[SurferD]

I'm just doing this now. When I took mine out I found that the cover was off and mast was broken.

So I'm looking for parts. If you have any spare stuff left over I could use it.

Edited September 11, 2016 by SurferD