Mazda MX-5: Fixing the Door Beltline Molding with NE51-50-640G from Avondale Mazda

UPDATE May 7th: After three days of light/moderate/heavy rain with the new beltline on the passenger door, I’m still having the same issue of water retention. Not a damn thing has changed, except of course I’m out $50 bux…. not thrilled about this! Maybe it’s part of the design to open the door so the water flushes out but it doesn’t sound too reassuring. Certainly wouldn’t want it to start rusting if the car sits around for extended periods of time in all types of weather. Argh!


Ever since I bought my Miata there was a peculiar phenomena happening. After heavy rain or even just washing the car, a bunch of water would pool in the passenger side door that would gush out when the door was opened (otherwise didn’t drain on it’s own).

I shared this video in April of 2015 showing the issue after it rained:

The solution was quite simple, but pricey!

I bought the new beltline molding from Avondale Mazda in Arizona through eBay using one of their $15 off $75 purchase coupons. The part was listed for $65+ and I added another $14 item that I was missing, a battery brace to help secure my DieHard battery (some schmuck that installed the battery for the previous owner didn’t put the brace back on)…. and now the battery is held on only by cables.

Anyway, it wasn’t easy to find instructions on how to remove the old beltline molding. The instructional videos from NA Miata, and the Miata.net how-to for the NB Miata are different. Luckily I had an NC Miata maintenance manual that showed a graphic how to do it. And in the process of attempting to release one of the plastic clips, I promptly broke it. I assume the plastic was brittle and didn’t take much effort to break.

Removal was easy. Re-install was a bit of a pain in the ass because of alignment. But eventually everything fell back in place. And I’m happy that there’s no more gap between the molding and the window. This week it will rain a lot so I’m going to test how the new molding is working out. But I think I’m happy with it!

As usual I took a million pix:

Old molding…

The new and the old molding… clearly the old one at 10 years of age is very much worn and lots of dust around it including some rust on the triangle part of the window to the front of the car.

Lots of cleaning was required.

Voila!

part#: NE51-50-640G for the Right Side.

part #: NE51-50-650G for the Left Side.

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