I rebuilt the two rear sub woofer speakers on my SRT Coupe using this kit . . .
https://www.ebay.com/itm/2-6-5-Butyl...0AAOSwCU1YtyvX
This is the second pair of sub woofers I've rebuilt. It is not difficult and the 13 year old sub woofers work and sound like new again . . .
An inexpensive fix for this inevitable problem on all Crossfire subwoofers . . .
I also found this YouTube video made by Crossfire Guru Paul Diguer. I suggest it will be helpful to watch this video before you start this project!
See step by step procedure below
I should have taken photos and posted a step by step . . . Sorry I didn't do the photos but here is the step by step procedure:
1) Move the seats all the way forward and tilt the seat back forward.
2) GENTLY pry off the plastic speaker grille from the top (it clips in at the top and bottom area of the grille). Note: these grilles become brittle with age. I suggest you use a putty knife (to help distribute the prying pressure on the brittle plastic grille) or if you have a curved "pry tool" that can be helpful.
3) Remove the plastic screw "cap" at the lower center area of the carpet near the console (it unscrews).
4) Remove the screw cap at the upper outside corner of the carpet area (it unscrews).
5) Removed the door sill plate (grab it from the back side with two hands and pull it upwards . . . it will pop off.
6) Pull the carpet from the lower outside corner and peel it upward and toward the upper center of the car (try not to break the rectangular plastic support piece attached to the carpet).
7) Remove the subwoofer speaker (three 10mm nuts). Disconnect the wiring connector (press on the little release clip and pull).
8) Repeat the procedure on the other side of the car.
9) Vacuum out the subwoofer enclosure area . . . It will have bits of the deteriorated foam speaker surround material in there.
10) Take the subwoofer(s) in the house and lay them on a work area with a padding (I just used a folded towel).
11) Disassemble the subwoofer plastic pieces (back piece unsnaps - speaker side has four torx head screws that allow you to remove the mounting ring and then the speaker itself.
12) Clean off the outside of the speaker mount area AND the outside edge of the speaker cone itself. I used rubbing alcohol, some "Goo-Be-Gone and a scrapper tool to remove all the old adhesive residue and the deteriorated foam.
BE CAREFUL NOT TO DAMAGE THE SPEAKER CONE!
13) Apply a bead of new adhesive (from your repair kit) on the outside mounting area of the speaker mount (put the bead around the
INSIDE edge of the mount area. Carefully place the new rubber from the repair kit onto the adhesive bead of the speaker mounting area being sure to "center" it. It will partially cover the screw holes (you will trim those little bits of rubber out later after the adhesive sets up), put the mounting ring in place (but don't screw it on. Put something across the mount ring to even out the pressure and and put a weight on it. Leave it to set up overnight.
(Note that if the speaker cone may have separated from that lower beige color fiber "spring" piece where the cone mounts, you can use the kit's adhesive to reattach the cone there. ONLY apply adhesive to the top lip area of the cone and reattach it to that fiber spring piece)
14) After your adhesive has set up securing the outside of the new rubber piece to the speaker mount area, insert the speaker into it's basket so you can use the adhesive to attach the speaker cone to the inside area of the new rubber piece. I used kleenex tissue gently stuffed onto each of the holes in the metal frame around the speaker to "raise up" the cone a bit. Then apply a bead of adhesive around the outside ring of the speaker cone (you can lift the edge of rubber piece as you go around applying the bead of adhesive onto the speaker cone).
15) Now . . . find an old CD disc and place the CD on top of the rubber piece and speaker cone . . . It is the perfect size to press the rubber onto the speaker cone. Put a light weight on the CD and let everything set up overnight.
16) Put everything back together and enjoy your rebuilt subwoffers!