My wife's '94 RX-7 broke off the nylon "rack" in its power antenna mast. According to the '94 FWM "Body Electrical Manual:"
However, when the tiny "rack," or toothed belt, broke, it left the great majority of it inside the antenna power unit. Here is what I actually had to do:

0) Order a new antenna mast ($54).

1) Remove the kick strip over the passenger side rocker panel.
2) Remove the "seam welt" around the door edge.
3) Unbolt the 17 mm floor bolt at the lower end of the seat belt and unhook the belt from the seat.
4) Pull 2 plastic "fasteners," one "installation screw" from the interior "quarter panel."
5) Pull the covers over the right and left rear coil towers.
6) Unbolt the rear "strut bar" and remove it.
7) Fold the trunk carpet, which is secured at its front edge, out of the trunk and into the rear storage compartment area.
8) Pull off the quarter panel piece through which the seat belt exits.
9) Pull the quarter panel loose (6 metal clips, 2 of which disappeared during this operation), and remove it.
10) Pull and remove the rear air extraction panel after pulling the "seam welt" from the rear trunk edge.
11) Remove the jack, wrench, and jack stand from the compartment inside the passenger side "trunk molding," after removing its cover.
12) Remove the spare tire.
13) Unbolt three 10 mm nuts that hold down the passenger side trunk molding.
14) Pull five plastic fasteners from the trunk molding.
15) Pull the "seam welt" loose from the passenger side edge of the trunk.
16) Remove the passenger side trunk molding, which pulls off two plastic locating pieces, both of which must be contact-cemented back on before replacement.
17) Remove the upper plastic nut of the antenna mast using snap ring pliers.
18) Remove the antenna mast, which has a 2 inch piece of the "rack" attached.
19) Disconnect the antenna power and RF connectors from the Power Antenna Unit.
20) Unbolt one 10 mm nut holding the Power Antenna Unit, and remove the unit, which has a drain tube that was threaded into an invisible hole somewhere in the lower region of the body.
21) Take the unit into the kitchen, place it on a large towel, unscrew five cover mounting screws, and remove the cover.
22) Remove the interior drum, inside which is wrapped the other 40 inches of plastic "rack." (Can you imagine what would have happened if I had followed the FWM's instructions?)
23) Pull all the gears and guide roller, clean, lubricate and reinstall (I suppose this was optional...)
24) Clean, lubricate and reinstall the drum.
25) Reinstall the unit cover.
26) Reinstall the unit, i.e. find the drain hole and thread the drain hose back through it (a blind operation), align and bolt it in place, and reconnect the connectors.
27) Get out the contact cement and glue the two plastic pieces back onto the passenger side trunk molding.
28) Look for the two metal clips missing from the quarter panel, find one, and reattach the clip to the panel.
29) Reverse steps 16) through 11) to reinstall the rear passenger side trunk molding.
30) Reinstall rear extraction panel and reinsert the seam welt for it and the trunk molding.
31) Thread the seat belt back through the quarter panel hole, align the quarter panel and pound it into place by hand.
32) Reverse steps 8) through 1).

At this point, the car was ready for its new mast... so I followed the FWM's instruction and faced the toothed side of the rack toward the front of the car. The unit would not pull in the rack... tried many times; the rack would just jam. So I had to do steps 1) through 21) all over again, i.e. tear the car interior apart, and try to start the rack in manually, on the kitchen table. The rack was quite stiff and didn't want to curve into the drum, but eventually got it about half a drum wrap in.

Back out to the car with the unit bolted together and the long mast sticking out, I found out that the rack teeth must face toward the rear of the car, not the front!! But finally, the motor pulled the rack in and the antenna now works fine.

So the manual mast replacement directions had two major errors:

First: Steps 4. and 5. cannot be done, since a broken rack leaves a large piece inside the power unit, and
Second: The rack teeth must face the rear of the car, not the front.

 

Yesterday I ordered one these for my 89 GXL:
Power Antenna Kit

The site claims it works for all models of RX-7.

If someone has a good method for plugging the hole left by the antenna, I would sell mine from my 93. There's no radio in the car, so all the antenna does is keep the water out.

 

You really don't need to take all that apart. Remove the back plastic panel at the hatch, unbolt the passenger plastic hatch trim from the floor of the hatch, and pull it towards the center of the car starting from the back. You should be able to get it pulled out enough to get in there and unbolt the motor and remove it.

Take motor cover off, remove broken nylon mast, bolt back in place, feed new mast in with antenna motor in "up" position, turn radio off so it will suck the antenna back in. Try it a few times to make sure it's working well, then button things back up.

I don't think the mast itself is that pricey from Mazda, either. The motors very rarely go bad. Also, make sure the drain tube for the motor goes into the hole in the body. If you retract a wet antenna, that's where the water will go.

Dale

 

Agreed. That's how I did it. But it doesn't make finding that drain hole any easier.
Wow...lucky me. I'd never win the lotto, but mine went bad.... ~ $140 for the assembly. But hey, it came with a new mast.

 

Dale,

Everything I listed was absolutely necessary. The passenger side trunk section is held not only by three 10 mm nuts, but also by four plastic fasteners, one of which is covered by the rear quarter panel. Trying to pull out the rear portion of the trunk section without removing the frontmost fastener would likely have broken its plastic tang off, not to mention that the strut bar is in the way of pulling it out toward the center of the car. At best I would have permanently bent the panel out of shape. As it was, even when completely free, taking it out ripped off two locating plastic projections at its rear, which (as I wrote above) had to be reconnected with contact cement. And I was as careful as possible. Even if I had done it the way you mentioned, and didn't destroy something, the antenna unit would have been very difficult to R&R, because the bent-out panel would have been in the way.

My main purpose in that long post was to point out the fallacies in the Body Electrical Manual, which if followed to the letter would have destroyed the new mast and forced a re-buy/re-do. The $54 for the new mast, from the local Mazda dealer, was at a discount from the "Retail Price" of $70.

 

Serious PITA!

I replaced my mast and the replacement broke about 2 weeks later... i plugged the hole and installed SIRIUS the following week. best mod yet

 

zenofspeed,

When you replaced the mast the first time, did you take apart the power antenna unit and remove the broken piece of rack that was left inside? If not, that was what probably broke your new mast 2 weeks later... The drum inside is sized to hold only one wrapped-up rack.

 

I've rebuilt the antenna in another RX-7.

Which is what prompted me to just order a new one this time.

Taking the thing apart, replacing parts, and re-assembling it all make the $50 replacement look like a good option.

I'll know in a few days ...

 

I recently replaced my broken mast piece also.
One thing that is a COMPLETE pain in the ******* *** is...getting that drain tube hooked back up....
Otherwise it isn't all that bad. It seems like I recall being momentarily perplexed by the mast rack direction also.

 

actually. I replaced the whole unit. It just happened to break too... I've never liked those antennas on any car. I usually removed them and plug the whole before paint.

You can install an internal antenna under the headliner that works great.

 

And of course keep in mind the FD has a 'diversity antenna' with one built into the rear glass anyway.

Personally...I just demand my cars have everything working...drives me nuts if even one little light bulb is out.

 

Really? I see only the rear defroster wires in the glass.

 

Look again...and closer. You will see the top 'element' is actually the antenna.

 

You're right. I even see in the manual one antenna "feeder" running down from the glass to join the cable from the power antenna. The only problem is I can't find any connection to the glass antenna in the "Audio" section wiring diagrams.

 

I replaced my mast with a Cheap $20 one from ebay and it stuck out 1/4 inch too much. So now I have the $50 OEM one on order.

Finding the drain plug was not that hard for me. If you shine a flashlight angled back though the large hole where the motor goes and look through the hole on top where the antenna mast comes out you can see it clearly. You just need to do this step before bolting the motor in place.