While I was laying my EFI wiring between the relay compartment and the cabin, I decided to replace the worn-out sound deadening material on the shelf. It was becoming worn and just wasn't holding up.
My plan was to replace the rubber and foam in the center of the parcel shelf with Dynamat, as I had done under the seats and on top of the parcel shelf boards. It then occurred to me that I had the relay compartment trays loose as as I was doing my EFI installation, and that this was the perfect time to install Dynamat under them as well. I ordered a Dynamat Extreme Door Kit, which has more than enough to do the entire parcel shelf. I also bought a cheap wallpaper seam roller, which is basically the same as the official Dynamat one but a quarter the price.
How Much Dynamat?
I bout one of the Door Kits, which includes five sheets of Dynamat Xtreme. This was enough to do the driver's side electronics tray area, wheel well, lock box area, and some of the parcel shelf back. I bought a second kit to finish the parcel shelf and the passenger side electronics area. I had done the battery area and the side panel areas previously. If you're doing this, you'll probably need at least three of the door kits. The Bulk Kits include 9 somewhat larger sheets (576 sq in vs. 432 sq in), and may be enough to do the entire area, and is a little cheaper than buying three door kits at the time of this writing. You'll need more if you also want to put Dynamat on top of the electronics covers.
Removing the Old Material
The parcel shelf has a layer of rubber over a layer of foam. I decided to remove all of this. I was able to peel off some of it by hand, but the bulk some of the foam glue was still pretty strong and wouldn't let go with brute force. The solution was just to use a paint scraper from the hardware store. This scraped off the remaining foam fairly easily. A shop vac picked up all the smaller loose bits that were too troublesome to lift out by hand. I wasn't worried about the residue, as the Dynamat would easily stick to it.
Removing the Electronics Trays, Side Panels, Speakers and Carpets
To do the whole area behind the seats, you're going to have to remove everything that's back there, including the side panels, carpets and the speakers. These can be a bit thought, as some things are glued down like the side panels and carpets, while others simply have a lot of other stuff in the way, like the electronics trays.
Behind the seats are two trays of electronics, one on each side. They are held down by two philips screws each. The passenger side tray should be relatively easy to lift out, but for the driver's side one you'll have to pull and unmount the relays as well via two small screws per row, and possibly pull through the bulkhead connectors and disconnect the positive and ground leads to get enough slack to lift the tray out. I was already doing a lot of electrical modifications for an EFI conversion, so I already had this take care of.
Once the trays are removed, the plastic trim panels that cover the speakers need to come out. These panels are held at four points:
- Seat belt, bolt (17mm socket)
- Front of the plastic panel on the door sill (philips screw)
- Door kicker, if installed (two philips screws)
- Folded over and glued tabs
The seat belt bolt is easy to remove; just flip down the cover and use a 17mm socket to remove it. It's a tight fit with a socket, so you might prefer to use a box wrench instead, but a socket worked fine for me. Keep track of the spacers on the bolt behind seat belt assembly so that you can reassemble them properly later.
The plastic panel has a screw on the leading edge on the door sill. You'll have to pull back the carpet to see it. It comes out easily with a philips screwdriver. The kicker then pulls right out.
My car has a spring-loaded kicker installed that pushes the door open. Two philips screws hold it in place. It must be removed for the plastic panel to come out.
The hardest part is is the plastic tabs that are glued over the edge of the door frame under the weather stripping. First pull off the weather stripping; it's just press-fit and comes right off, and will be easy to push back on later. The tabs are part of the plastic panel, folding over the edge and are glued to the lip. What you'll need to do is slip a knife or a small (as in, jeweler's sized, like for working on small electronics or eyeglasses) flathead screwdriver to break the glue, carefully prying up the tabs. Once you get a few of them free, you should be able to slip them over the lip and then move on to the next set of tabs. You will very likely break off a few tabs, but as long as most of them are intact, you'll have no trouble reassembling it, and the tabs will be hidden when you reinstall the weatherstripping.
With all the tabs unstuck and the bolts and screws removed, the panel can pulled upward and forward until it is free from the body. Since the seatbelt is still attached, you won't be able to completely remove it form the car.
Wheel Well Carpets
There are carpets over the wheel wells that have to come off so that you can put Dynamat under it. The carpet sits on a layer of rubber, which sits on a layer of foam. The glue under my driver's side carpet was well worn, and I was able to lift it off of the rubbber-and-foam backing with little effort. I left the foam-and-rubber in place here. On the passenger side the carpet was firmly attached to the rubber, so I decided to remove the entire carpet-rubber-foam sandwich. I wound up getting the carpet and most of the rubber/foam in one large piece, most of the rest of the rubber and foam in a second large piece, and had to scrape off the remaining foam in a third piece.
You can also pull the carpet up from the lockbox behind the driver's seat so that you can sound dampen that area as well. With the electronics try out, it's pretty easy to just pull this out from the top; mine wasn't glued in at all. The passenger side area contains the battery, so no carpet needs to be removed there; just pull out the battery so you can cover that area with Dynamat.
The speakers are held in place with large hose clamps, which are easy to loosen with a screwdriver. The speaker then just lifts straight off, along with the clamp.
I also removed the speaker bracket so that I could put Dynamat behind there as well. It is held on with three philips screws.
It's up to you if you want to remove the seatbelt bracket. I left it in place and Dynamat'ed around it.
Installing the Dynamat
I did the passenger side electronics area first, then the driver's side, then reinstalled the trays before doing the center, mostly because I had to push the trays into the center to do the area under them.
Dynamat comes in sheets, in this case 18" by 36" sheets. It can easily be cut with a utility knife to whatever shape you need. The edges of the metal-backed deadener can be sharp so be careful when handling it -- I cut my thumb soon after I started laying down sheets.
Each sheet has its own adhesive backing, so all you have to do is cut it to shape, remove the backing, and stick it on the shelf. This backing is pretty strong, so be sure you place it correctly the first time. It's best to start at one end and push it down as you go. Buying a small roller can make it easier to ensure that you really got it into the corners and that it is pushed all the way down. You can get an official Dynamat roller, or a much cheaper wooden wallpaper roller.
It's tempting to use big pieces, and that works well for the large central area of the parcel shelf, but for everything else it's a lot easier cut the sheets down into a smaller, more manageable size. Try not to leave any significant gaps, though, as sound will make its way through. However, there are a lot of places that you can't cover with Dynamat (like the rear window, the holes in the pontoons to the bulkhead connectors, etc), so you don't have to be perfect.
It is also important that you keep track of any screw holes and access holes as you go. I cut an 'x' shape over the bolt holes and used the utility knife blade to push the corners away from the hole, then used the roller to push the mat down once all of the holes are punched out.
Reinstalling Everything Else
I used 3M Super 77 Spray Adhesive to glue the passenger carpet back onto its rubber-and-foam backing, and then glued bother carpets back into the car over the Dynamat. It's specifically deigned to glue headliners and carpets down, so it's a good choice. It's up to you if you spray it on the carpet or the mat, but I decided to go with the carpet to ensure I got the coverage right. I wasn't quite sure how much to spray due to the porous nature of the carpet, and probably went a bit overboard on the passenger side.
My lockbox carpet wasn't glued in, so I just placed it back in where it belongs.
The side panels go back on the way they came off. Watch the engine cover release handle while reinstalling the driver's side panel. I did not glue the tabs back down; I simply slid them back over the lip and pushed the weatherstripping back down on top of it. There'll be enough residual glue under the tabs to keep it stuck back down, and the weatherstripping will keep it snug. I've taken these off a few times now, and it gets easier the more you do it, especially now that the bulk of the glue is gone, but you still have to beware of breaking the tabs.
I had a little bit of trouble with the seatbelt bolt on the driver's side. For some reason the plastic panel didn't align quite right with the hole. It seems like it had been that way for a while, as there was an indent in the hole in the panel where the bolt goes. A bit of fidgeting finally got it installed, though. Don't forget the spacer on the seatbelt bolt!
These just go back in the way they came out. Nothing really complicated here, as long as you remembered to leave the screw holes open in the Dynamat. These are M5x1.0 screws, in case you lost any of them.
And that's it. You should now have a somewhat quieter ride. I have to finish my engine upgrades before I can actually test it myself, so I'll have to post results at some future time.