Thanks to lupogrover for getting me started in the right direction. My Solara is a 2002 but seems the same.
The 4 nuts holding the back seat on are 13MM. Before you can pull the seatback off, you must remove the plastic assembly across the top that holds the seatbelt guides. It is held on by 3 phillips head screws that are hard to find but easy to remove.
Best way to remove the woofer is with a SHORT 10MM socket wrench because there is a brace across the back of the car, right in front of the top screws.
Looking for a new speaker is NOT that easy. I tried. The original JBL 86160-AA310 has a double voice coil, so there are 4 wires going to it. The design is unusual--9" diameter with 4 mounting ears. The plastic box it mounts to is only 3" deep. The fact that it’s rated 4.6 ohms is no big deal—a 4 ohm speaker is just fine. So’s a 6 ohm speaker. The problems are the physical dimensions and the 4-wire hookup.
So you have 4 options:
1. You could buy Toyota Part No. 86160-AA310 for about $200—a total rip-off for such an unimpressive woofer.
2. Find another 8” or smaller DUAL VOICE COIL woofer that has two sets of connectors and is no more than 3” deep, and fabricate an adaptor plate. Basically a piece of plywood or plastic with a hole in it the correct diameter for the new woofer. screw the adapter to the plastic housing, being sure to caulk it well to avoid vibrations.
3. Send your woofer to a reputable repair shop like Millersound in PA to be repaired.
4. Repair the speaker yourself.
This last option has been used by vintage speaker fans for many years. What has (usually) happened to the woofer is “foam rot.” The foam ring (called the surround) that attaches the paper cone to the metal frame has deteriorated. This is a design flaw in a car speaker, IMHO. The surround could have been made of butyl rubber, which does not rot and would do better in an inhospitable environment. Fortunately, the surround can be EASILY replaced. You just have to buy the correct “kit” from an outfit specializing in such things.
Again, JBL screwed the consumer. The non-standard impossible-to-replace woofer has a non-standard hard-to-find surround. They did NOT want you to DIY!
Several sellers have the correct surround. I always buy surround kits from M_Sound. This site has step-by step instructions and a link to his ebay store. You can just email him and ask for a kit for this speaker. It will cost about $13.
http://www.citlink.net/~msound/There are other sellers. I found one offering the kit for $13, another for $25 and another for $50!!! To repair ONE speaker!!! And these are reputable outfits. Do yourself a favor and go with M_Sound.
So I bought the surround from M_Sound, repaired the speaker and reinstalled it. The repair itself takes an hour or so, then you let it dry overnight. Because I did not care for the boomy sound of the JBL sub, I put some dacron polyfil (from a fabric or craft store) in the enclosure to try to dampen it a bit.
That’s it! It cost me WELL under twenty bucks and the hardest part was getting the seatback out![/size]