What are those caps right underneath the storage bins, under the car called and where can I find them. I'm missing one and its letting in moisture into the storage bin. There's like this heavy duty carpet/ rubber material that prevents most of it getting to the carpet in the storage bin. Just need to get one of those caps.

 

Bodyshop supply, autozone help rack, junkyard, ebay... keep looking until you find the right sized one.

Put duct tape on both sides to close it up temporarily and shoot some undercoat on the outside to seal.

 

Getting moisture in the body under the storage bins is bad news, especially in Michigan. A good way to rot a car really fast. That heavy duty carpet/rubber material just makes matters worse by trapping the moisture so it can continue to rust out the wheel wells for months at a time. I'd suggest you remove that soaking mat pronto and put it out in the air to dry out, then mop up any moisture underneath. This is also a good time to check for rust and arrest it if you find it, chances are it's there in a Michigan car with a missing drain plug.

Those plugs, obviously, keep the moisture out. They are nice to have so you can create a drain to remove water from that area when it gets in, like when I forget to close the sunroof and we get a driving rain. Other than that, they need to be in place.

I have some extras, send me a pm with the exact diameter of the one you want and a mailing address and I'll send one out (there are several located around the car, I'm not sure if they are all the same size).

In the mean time, take Devil's advice and tape up that hole today!

 

Thanks for the advice I'll look at as soon as I get in the shop! Was almost -30 with windchill today lol

 

Mazda still has them, however the picture isn't very good, so looking them up is a PITA

 

305-Pc Plastic Plug Button Assortment - TP Tools & Equipment

 

Here's what it looks like, it is 2 inches in diameter underneath the driver side seat. That's the exposed rug / rubber like stuff lol

 

here is the pic from the parts catalog, which is a scan of a book, into microfish, into a computer...

i'm thinking its C, which is the big metal hole cover (6" diameter) with a little rubber plug in it

 

Here's some actual pictures of the actual plugs in the FB.

The big ones (2" outer diameter, fits hole size 1.4") are found in the rear hatch area, under the spare tire space.

The middle sized ones (1.5" outer diameter, to fit a 1.1" hole) are from under the storage compartments.

The little ones (1.25 od, .75" hole) are most likely from the floor panels, but I didn't run that down.

 

Could somebody with an 84/85 FB verify that the drain plugs shown in the photos above are correct for the 84/85 models?

I used my 83 GSL for comparison to assign their placements and assumed things didn't change for the 84/85 models, but maybe that's not a good assumption.