Mastic sealant pads

  1. My model of MX-5 is: NA_
  2. I’m based near: Northumberland
  3. I’m looking for technical help or recommendations on: mastic sealant pads/sheet

Unhappy with the interior side of my floor pans, probably due to water getting into the car and soaking the (binned) old carpet due to the (long since replaced) window hood seals I’ve been stripping back to bare metal etc. I had to take all the mastic off as apart from anything else water had got under the edges of it and this is where it was worst.

It appears Mazda put down mastic pads over the bungs in the floor pan. These appear to have been laid over sealant/ seam adhesive in places.

I want to apply pads again, over sealant where necessary, as opposed to just using a caulking gun. I can see various mastic pads or sheet for sale but does anyone know which are the good brands? I can see some 3m stuff but as 3m’s idea of product display is to show a picture of their logo I don’t know which is suitable.


The large black bitumous pad in the floorpan is sound deadening. If you’ve only removed a small area around the bung personally I would leave it missing but if you want to refit there’s loads on ebay, they’re just a dense self adhesive pad to attenuate high frequency road noise. If you’ve found some by 3M then they will be good.

Its important to take out any failed seam sealer, which on the underside of a MK1/2 will be most of it, clean back anywhere rust has got to, reapply new seal sealer and then put some sort of protective coat over the seam sealer and exposed metal.

Thanks - I’ve ordered 3m and white Seam sealer. I like it original.

All the sills and floor (inner outer strengthener and into the a &b structures ) are remade where replacement panels were not available and the arches and rear qtr done too and I’m still pulling old sealer out here and there.

Bits of the square plugs that sit over the chassis rails had been done with black seam sealant by the welder when the beefed up mx5 restorer rails were added (things of great joy) but I’ve pulled all that out to put the correct white in.