Hard Dog Fabrication

Mazda Miata NB (1999-2000) Door Panel Retrofit into an NA Miata (1990-1997)

by Jared Connell


I attempted this mod having long envied the NB Miata’s stylistic streamline sports car interior. Basically, when Mazda re-designed the body of their famed sports car in 1998 to make production in 1999, they did a complete overhaul much like they did for the NC. This included a complete interior re-design and a complete exterior re-design. They did change the inner door shell of the Miata quite a bit, but the size did not change and the handle position only changed minimally. So, with only minor modifications, the NB panel can be fitted to an NA door shell. NOTE: I am referring to the 1999-2000 Miata door panel; I have not yet tested the slightly re-designed 01-05 panels.

Factory Door Panel Removal:

To start off, take a Phillips head screwdriver and remove the single small Phillips head screw that holds the door handle bezel to the handle (store this for later!) Remove this bezel by locking the door with the slider, lifting up on the latch handle, and pulling the bezel out towards the end of the door. Next, you must remove three Phillips head screws from your factory door armrests, the top most screw is covered by a plastic piece (some of you have door pulls only, in this case you will only have two factory Phillips head screws.) Next, you must remove your factory door panels by popping loose the white and sometimes blue upholstery clips that fasten the panel to the door. On some NA model door panels there is also a single screw that holds the panel on at the rear, this will need to be removed as well. Simply lift up on the upper black panels now after having popped all the upholstery clips and loosen it from the windowsill and you should now be able to completely remove the panels. Do the same on the opposite door. Lay these panels to the side, as you will be using a part from them in the near future.

Factory Handle Removal:

Next, you will need to remove your factory door handles, to do this you will again need a Phillips head screwdriver. The factory handles are mounted into plastic factory inserts in the inner door shell by three Phillips head screw/bolts. First, pop out the plastic connection piece that the factory door latch rod connects into the handle. Leave this hanging as you will be attaching it to the NB handle after you get it mounted. You can completely remove your factory lock/unlock rod from the door as it is just a nudge to short to use with the NB handle. You will need to fabricate your own, which is very simple just a rod bent in a couple of places attached to both the handle and the lock for the slider to operate it. The factory NB lock is a cable mechanism and it would be hard to use this system without completely replacing the lock/latch mechanism, but construction your own stiff rod would be quite simple, out of a stiff close hanger if you like.

NB Panel Preparation:

Now you can go back to your NA door panels, and remove the window trim pieces from the top of the panels (runs along the window… it is a metal piece with felt and rubber that the glass rubs against as it goes up and down… there is also a smaller one that the quarter glass is against.) These pieces detach by a series of metal tabs that will need to be gently bent back straight, then the pieces just slide off. Do the exact same with your new NB panels and swap the trim out. Now you have a perfect alignment of the quarter window and the window glass itself! (NOTE: this may not be necessary, test to see if your NB panel lines up with the windows)

Next, flip your NB panels to the reverse (inside), and look up top near the window trim. There should be two plastic “clips” that Mazda used on the NB to fasten the top part to the window sill/door shell. You will need to remove these plastic pieces that are riveted on (2 rivets one each side). To do this, I used a pair of pliers and simply applied lateral force until the rivets popped loose.

Next, using a box cutter/Exacto knife etc., shave down the lower extended piece of Styrofoam from the NB panel inside (you will see it as it’s the only piece that sticks out from the rest of the panel.) You want to shave it off until it is level. Feel free, while you are looking at this side of the panels, to remove any Mazda upholstery clips (same as on your NA panels) from the NB door panel as you won’t be needing them to attach the NB panels to the door. (at least I didn’t, but if you like to drill new holes and be able to pop the NB panels in but the tabs are in different places. You can do this too, but I simply made new brackets out of aluminum for under the door to hold the bottom of the panels on).

Next, you will mostly likely need to remove the NB factory tweeter and white plastic mount as they will probably stick out too far and deter the new panel from proper fitment to the door. What I did is use my own smaller tweeters (Infinity Kappa) and retrofitted an aluminum bracket to mount them to the inside. You will have approximately an inch of room to work with regarding tweeters if I remember correctly.

Test Fitting NB Panels:

Now, with your old handles and panels of, you should be able to test fit the new NB panel to your door. You may need to take a hammer and gently ding in this area on your door panel (only slightly) to make room for the rear of the NB panel armrest:

You may not need to do this at all.. I just did instinctively did after doing it on the driver's side to the passenger's side without even testing it to see if it is needed.

You should now have a perfectly fitting NB panel to an NA door!

Now, if you choose to affix the bottom of the panels like I did, you make brackets like these:

You don’t, by any means, have to do it this way, this was just “quick” for me and definitely did the job! There is actually another angled screw hole just under the small piece of carpet on the inside of the door handle that can be utilized to affix the bottom of the panel to the door. You can also do like Mazda did on the NB and use the plastic upholstery fasteners, but you will need to drill new holes for them to pop into as they are in different locations than on the NA. Also, on the side of the panels there are two holes that in my installation weren’t used. To use these, you can simply get two 90 degree brackets and mount one side to the door and the other two the inside of the panel and you can even use tan Mazda push button clips like the ones that fasten the trim pieces on here. There are a multitude of ways to adhere the panels to the door shell other than the way I did it.

Now, make sure you have the panel centered and positioned in the way it is supposed to go on the door and you can begin drilling your mount holes. First there is a clear hole in the black upper tweeter panel under where the door panel meets the dash. Simply drill the appropriate sized hole and re-use one of your factory Phillips head screws from your door armrest/pull here to fasten the panel to the door shell. Next, you’ll need to look at the upper part of the NB door pull, and you will see a screw mount location. Mark the location to drill while the panel is fitted properly to the door and remove the panel again to drill this hole which you can also re-use one of your factory door pull/armrest screws:

Do the same to the opposite door panel.

NB Handle Positioning:

Now after making the brackets, securing the panel at the upper door pull, and securing it at the upper tweeter panel, you should have a VERY secure panel without a handle. Now you can see where to position your new NB handle. You can slip it in through the hole and approximate where to drill the holes. Try to get it as centered as you can as when the bezel is in place if it is a tad off you can tell by the molded door panel frame. You will need to do the following to the NB door handle for proper fitment (refer to the picture for visual reference):

After you get the precise position of the handle, mark the hole positions, remove the handle and drill the appropriate sized holes to re-use the original Mazda screw/bolts that held your OEM handle in place, do the same for the opposite door panel.

Once you have your new handle mounted, you can remove the NB panel from the door. Take the plastic piece from the latch mechanism on the NB handle and reverse it, it will be pointing down, you want it pointed up. Once you remove the piece, you can fit it to your door latch rod and take some pliers and fit it through the hole on the NB door latch mechanism of the handle. Then you will need to use the door lock/unkock rod you've made to attach to the lock mechanism to the handle, this is very simple. Again, repeat for the opposite door panel.

After mounting the handle (re-using two of the Phillips head screw/bolts that originally fastened your OEM handle in place), depending on your interior color scheme, you may be done! However, if your Miata has NA tan, then you will have already seen that the NB tan is not really “tan” but rather beige and will need to be dyed to match your interior.

Final Fitting:

Here’s a couple of pics of my final testing of the passenger’s panel before dying:

Panel Dying to Match NA Tan (Camel) Color:

Now for those of you wanting to match the NA's tan interior with the NB's beige, you can take your NB panel and completely disassemble it as shown here:

For dying I highly recommend what I used, SEM color coat CAMEL vinyl plastic dye, as it is already an EXACT match. Or, if you choose you can take a sample and have a paint shop match it, whatever you prefer.. I also used a gloss black vinyl/plastic dye for the tweeter panels and the handles. Either way, you will want to prep everything with lacquer thinner, and you will want to prep any hard plastic pieces with an adhesive promoter. Then you are ready to dye, follow instructions supplied with your dye. Again, repeat for the opposite panel.

Panel Re-assembly and Final Installation:

You can now re-assemble the panels and attach them to the door for final fitment. Slide the door handle bezels on and attach using the same philips head screws used to attach the NA's handle bezels on and you're done!

Pictures of my finished product:

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12 September, 2006

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