What? You mean your wonderfully well designed power antenna broke? </sarcasm>
New tip here maybe, maybe something already covered, but as long as the actual motor is still working, then you can replace the antenna mast and the plastic drive cable in about 10 minutes. Trust me, it’s a bitch trying to straighten out the factory mast (in my case, my antenna wouldn’t go up or down all the way because it was bent, and as I found out after removing it, cracked).
First, go to your local dealer and order part 39152-SD4-305 - this ran $55 from David McDavid Acura, Plano TX. This part is the entire antenna mast and cable; David McDavid had it in stock and said that they used the same part on tons of cars, not just Integras.
Second, you can use either long needle nose pliers or the “antenna nut wrench” that Acura makes - my factory service manual says it’s part 07JAA-0010008, but they may have changed the part number by now. If you don’t mind a couple of scratches on the chrome piece on top of the antenna housing, use pliers (I did). C’mon, who’s going to look closely at what they call a “special nut” anyway (I got a special nut for them right here… er I mean…)
Now - with the antenna up or down (doesn’t matter), use your “special antenna nut wrench” (i.e. your pliers) to unscrew the top metal nut:
Pull then nut away:
Now remove the plastic spacer and rubber bushing (they’ll probably come off together, like mine did):
Now, turn on the radio, jump out of the car, and “help” the antenna to make sure it goes up as far as you can get it. Once the motor stops running, you should be able to give the base of the mast a good tug and it should pop right out. There’s another metal piece 3 or 4 inches long that will come out with the base of the antenna.
The plastic drive cable should come out relatively easy - you may need to give it a couple of tugs, just don’t pull it too hard - you don’t want it to break inside the motor!
Pull the whole thing out:
Installing the new mast is pretty much the reverse of removing it. Make sure you keep the radio turned on for this, and this part is a little easier if you have someone helping you.
First, this is easier with the mast extended, but it really doesn’t matter much as long as you make sure the teeth line up right.
Take your new mast, make sure the plastic teeth on the drive cable are facing the BACK of the car. Feed it in to the motor as far as it will easily go. Now, either rest the mast on the hatch, or have someone hold it - turn off the radio and start feeding the cable and mast into the hole, making sure that the metal base (which can be difficult to insert) goes into the hole. If you can’t keep up and it starts clicking and shuts off, don’t worry, once the cable is engaged to the motor you’re home free. Just make sure you get the metal base of it all the way in the hole, then run it up and down a few times to make sure it’s sensing the positions properly (you may hear the motor clicking the first couple of times).
Reinstall the spacer/grommet/nut, taking care to get it just tight enough to keep the antenna from being moved back and forth (if it’s too tight, the antenna may not go up and down or may stick). Service manual says it should be tightened to 1.7 lb-ft - basically not much more than finger tight, but if the threads are rusty or dirty, you may need to go tighter to get the grommet to seal again.
Now go show off your shiny new shaft to the world 
