Soundproofing 101

This shows the carpet and the front door vapor barrier. Note the lack of insulation on the kick panel.	This shows the back side of the carpet along with the bare floor. Note the carpet backing is all there is.	This shows the rear of the cabin. Once again, no insulation, and on the door, only the vapor shield.	Note the small patches of 'insulation/sound deadening material on the floor. The interior of the doors is similar	Just for your information, this is what the dash looks like when it's taken apart. (Picture credit  - Kim Lux)	This picture shows a close up of the factory insulation (or lack of ) Note that it's not very thick. (Picture credit - K. Lux)

Now came the hard part. In Kim's article, he told of using a homemade soundproofing mat by sandwiching the following: '8 pound' carpet underlay, 1 pound per ft^2 lead sheet, '8 pound' carpet underlay and 3 mil vapor barrier. To make this 'sandwich', he used contact cement between each layer. Approximately a gallon of cement is required. The result is a mat that is approximately 5/8" thick. The final touch is to use Spray 99 to adhere the vapor barrier to the foam. It is recommended that the mesh on the foam is toward the vapor barrier.

I embarked on trying to make this mat, but ran into an immediate problem. I could not find the sheet lead. This was once a common item, but is not as common as it used to be. If I could have found the lead, I would have made this since it is the cheapest solution and I feel would work quite well. Now my research started up again. I had read about Dynamat and then ran across an article from Dave (Just4fun) that pointed out several different options. My search ended up at B-Quiet for materials. I sent for samples and soon received them. From all I could tell, similar to others, but less expensive. From the beginning, I decided that there were some areas that would need doubling and possibly tripling up. From my calculations after taking to Dave,  I figured that I would need about 150 ft^2 which was 2 big rolls. After more research,  I decided on using the 'Brown Bread' . B-Quiet did have some material that was more like Kim's mat, but it was much, much more expensive. By now, my approach was to install the 'Brown Bread' and see just what the results would end up being, before any additional materials were added. Then,  if needed, I would try again to find the materials for Kim's mat or order the more expensive soundproofing.

Now comes the fun part. To strip the interior you will need the standard, metric, torx bits and screw drivers. To cut the 'Brown Bread' you will need scissors, a razor knife, straight edge, rubber gloves and acetone. (After cutting some of the material, use the acetone to clean up the blades.) You will also need some type of cleaner and some alcohol to clean the floor pan prior to installing the sound proofing. I found that paper towels worked quite well to clean. Before you start, make sure that you have the right size sockets, and torx bits. ** The seat belt bolts and the seat bolts seem to be the only unusual sizes. Also check for the deep well socket for the seat bolts nuts. A long screwdriver does help with some of the clips for the covers and a small hard (wood) wall paper roller is necessary.

First you will remove the seats and seat belts. If you have an electric seat, don't forget to unplug the connection. Next you can remove the console. Once again, if you have any electronics (like CD player) make sure you remove all electrical connections. The bolts for the console are located beneath the rubber mat at the bottom of the storage area. At this point, remove all of the door treads on the frame. These are all snapped in place.  Once these are removed, remove the door seals (You will want to label these for reinstallation). I then removed the pillar covers (a few screws and mostly clips), the rear tray (screwed in three places), and the rear cover (both screwed and snapped).  About the only thing left it the 4x4 shift boot (if equipped) and the regular shift boot (if equipped). For the 4x4 shift boot, it's easier to just remove the shift linkage from the main body.  The carpet will come out with out much problem.  I chose to clean the carpet while it was out, and it really cleaned up good!! Now you can see just how little soundproofing your truck has. I finished the interior uninstall by removing all of the door covers and the plastic weather shields underneath. Be careful with the plastic weather shields to not tear them. If you look inside the door, you will find that they also have a small patch of sound material on the inside of the outside door skin. You will also notice how little soundproofing is in the pillars and the beam across the back, under the rear window.

The next step is to clean all of the surfaces. I used Simple Green for the first clean and regular rubbing alcohol to remove any other grease/dirt. Some areas might require a little acetone if the paint comes off quiet easily with regular cleaners. Be careful not to get the acetone on any finished, exposed surfaces. Do not use up all of the acetone since it comes in handy for cleanup of the tools to cut the 'Brown Bread' along with any areas you might need to trim after installation.

After cleaning, you are ready for installation of the material. Get an area that will allow you to roll out the material and also cut it. A piece of plywood will work, but remember that you will be cutting the material and will score the surface. First you will learn very quickly to not go over 2' square because of the material can be hard to handle once positioned and the backing is removed. The first place I did was the interior of the doors. (By interior, I'm talking about the inside of the exterior door skin) I cut a piece that would roll up, and then fit inside the door cavity without folding. It will not cover the entire surface, but as long as it covers a lot, it will work. You might find it easier to use two pieces with one piece from the door guard rail bar up and the other to wrap the guard rail bar.  I started the backing and pressed the top of the material as high as I could get it and then pulled the backing off, as I rolled the material onto the door surface. You will need to roll the material with the wood wall paper roller to insure good adhesion. After doing the inside of the door, I decided to to the interior door skin, using the plastic weather shields as a template. Be careful not to make the material cut too large as it will interfere with installation of the door panel. I opted to just go over the wiring, and cut holes where the wiring came through the weather shield. You can remove the guides for the door locks, but be careful when you reinstall to make sure the door lock mechanism has enough unrestricted travel. As before, remember to roll all of the surfaces to help with the material adhesion.

Before doing the rear wall of the cabin, I partially filled the cross beam, just below the window, with OEM expansion foam. This did cut down the hollow drum sound, but I'm not sure that it helped that much. I also did the same thing to the bottom of the pillars. (You will see that in the bottom of the pillars, there is already a little insulation.)

Next, I started in the back of the cab, since it is the flattest and has the least curved surfaces.  This is a picture of the rear of the cab after a few pieces are installed.

As you look at the picture, notice the black area on the back wall. This is a cabin air pressure release vent. DO NOT COVER IT!!! Not only does it allow the air pressure to vent when you close the door, but if the air bags ever deploy, it allow the air to escape. Notice how the door lock cutout is low so that the latch bar is on the outside of the material. Make sure that the bar has clearance to move. Also notice how the wiring is underneath the soundproofing material. It's important that you do not have the material larger than the plastic weather proofing liner. If it is, the door panel will not fit. I also found that the door panels have plastic standoffs that need to be slightly trimmed to allow for the extra thickness of the soundproofing material. Go ahead and match the inserts of the door panel to the door, and cut out where the plastic inserts go. I went ahead and put the vapor barrier back on, as it helps to locate various holes that you will need to cut out. It will also give you a guide to trim, if your material is too wide. You do not need to force the door panel to go back on!!

As you trim for the pieces, allow an half inch or so for overlap. Roll all pieces down firmly. Start with the larger areas and then move toward the smaller, more curved areas (such as the front floor board). Do not put the soundproofing in the 'valley' next to the door where the wires that run from the front to the rear. If you do, the door sills will not go back on properly with the carpet back in place. If you are going to add any extra electronics, (such as a boom box, or better speaker wiring) this is a good time to go ahead and install the necessary wiring.

The pillars are similar to the other areas as far as installation. You will only put one layer on the pillar, otherwise the cover will not fit back on. Also pay close attention to the shape of the cover. You do not want the sound proofing material outside of the reinstalled cover. If you need to trim, allow an extra quarter inch inside the cover, and you can use the acetone to clean up the 'tar' from the soundproofing.

When I started the front floorboard, I planned on using at least two layers. This allowed me to use some of the scraps for some of the curved areas. Overlapping the bottom layer wasn't as critical, as long as the pieces butted together tightly. For small gaps, just stick in a filler piece and firmly roll. I used larger pieces for the top layer.

Under the dash, I even applied the material up around the steering column area, first laying the bottom piece under the plastic edge, and the upper piece overlapping the bottom. As you can see, I put the material up as far as I could get it, and double layered it.

If you do all four doors (one piece inside and one on the inside skin), the back wall, the pillars, the rear floor, 2 layers one front floor board, and 2 layers on the tunnel (**I only put one layer under the front seat!), you should have a few feet of material left. I found a good place to put this 'extra' material.

In the engine compartment, take a look at the area under the intake for the HVAC. Air for the HVAC enters on the driver's side and crosses to the passenger side. Just underneath this area is the turbo. I cleaned this area along with the area of the firewall that was not factory covered. My primary objective was to put the insulation on the underside of the air duct. This would cut down on engine noise coming through the HVAC system and reduce heat in the supply duct. I used the remaining scraps to do the area around the steering column and brake assemblies.

This is the passenger side of the engine compartment, showing some of the soundproofing on the bottom of the cowl air duct.

This shows a little of the soundproofing on the driver's side of the engine compartment. I also put some of this insulation just under the factory insulation shield (around the turbo/transmissions area).  Notice the 'can holder' on the firewall. For more information on the 'can' look here!!

The results?? It did reduce the interior noise substantially although I think that there is room for further improvement. The decibel reading on a 2000 stock truck were **** and the reading on my truck are ***. Unfortunately, in my truck you can hear the turbo much more. This is probably because the intake for the air box is through the fender well. (This is only on the early 99 trucks!!) There are two areas that I feel need improvement. The first is the inside of the front fenders to the door area. The second is the front floorboard/under dash area. Here I think I will try the composite material or try to make a composite like Kim Lux suggested. Using the decibel meter, that is where the most noise seems to originate. I'm sorry that I did not have the meter prior to installation, but it is helping to track down noise 'leaks'.

By the way, under the truck, at idle, there was a reading of 106 decibels while inside the truck the decibel reading is only 68!!!