The frame rails on a Mazda MX-5 NA and NB are the first point of contact with a high threshold, especially on a lowered Mazda MX-5. Although even original MX-5s sometimes have a threshold or driveway where the frame rails touch the ground. Unfortunately, this can cause quite a lot of damage to the frame rails which, over time, also results in rust.

Torn or severely rusted frame rails can result in MOT rejection during a MOT inspection.

After being asked several times if we could repair this and if there might be repair panels for sale, we developed them ourselves.

Important here was that the original bolt holes, drainage holes and dimensions match the original to get the most OEM/Original result possible. We did choose to make the Mazda MX-5 frame rail repair panels of a thicker material than original. 1.5mm instead of 1mm. This provides more rigidity in the chassis and better protection of the frame rails when in contact with the road surface….

The repair panels have 40mm spacing between pro welds for the most OEM look possible (OEM is 40-50mm). Remember that in the Netherlands this officially needs to be 20mm for the APK. If necessary, drill additional holes in the repair panel yourself.

The original frame rails are spot welded every approximately 40-50mm. These are easy to drill out with a drill bit, after which the sheet metal can be split with a hammer and chisel. In many cases, it is easier to replace the complete piece of frame rail.

The new frame rail repair panel can be pressed against the floor of the Mazda MX-5 with a jack or bucket support. This way you can immediately see if the floor is still completely flat. If this is not the case, then before welding the Mazda MX-5 frame rail repair panel in place, one should first level the floor with a plastic or sheet metal hammer so that the repair panel fits properly everywhere.

After the welding, we always use a body seam sealant to seal the seams, a Dinitrol stone chip coating ensures that the frame rail repair panel is well protected from the weather and finally, the Mazda MX-5 frame rails are treated from the inside with a Dinitrol cavity wax. All this gives the repair an OEM appearance and good anti-corrosion properties.

Does this seem like a job you can do just fine by yourself? Through the link below you can easily order a Mazda MX-5 Frame Rail Repair Panel: