Mazda MX-5: how to rust proof your classic car

3rd Aug 2018

A classic MK1 or MK2 Mazda MX-5 is likely to show signs of corrosion if not treated with a rust proofing. This is even more likely if it has undergone a restoration and had seams welded together. A Mazda MX-5 which is used as an everyday car and driven in all weather conditions across motorways and narrow village roads with speed bumps is exposed to scrapes, bumps and stone chips - exposing bare metal could lead to rust.

Dintrol  Mazda MX5 rust proofing kits includes all the products needed for the treatment and prevention of rust. If you want to prolong the life of your classic car here are the steps to follow to get the job done to a professional standard. All Dinitrol rust proofing kits purchased have a spray diagram for your car model to help you to get a thorough job done - as explained in this article.

Rust proofing is done in three key steps: convert all signs of rust, apply rust proofing coating and finally apply a sealant.

How to rust proof your Mazda MX-5

  • Wear protective clothing 
  • Jack-up your car as high as possible to get a full view to the undercarriage of your Mazda MX5 and apply a thorough rust proofing
  • Disassembly - remove wheels, mud flaps, plastic arch liners and all plastic trim covers fitted around the vehicle and undercarriage to allow full access to apply rust protection treatment applications
  • Use a hose or jet spray to give the underbody of your car a thorough cleaning - make sure the wheel arches are clean including the inner lip
  • Leave your car to dry - in this lovely hot weather your car should dry off within a couple of hours
  • Remove sill guards to allow access to the inner sill to apply cavity wax
  • Inspect for any signs of corrosion and treat with DINITROL RC900 rust converter. Use the wand included in your rust proofing kit and push it as far into the cavities as possible. Withdraw wand very slowly while spraying the RC900 all the time to ensure surfaces get a good coating
  • Give under carriage and chassis a thorough inspection particularly where corrosion is likely to occur

  • Spray on DINITROL RC900 to areas of bare metal and where there is rust. After application, allow 6 hours for the rust converter to work. 
  • Apply DINITROL 3125 cavity wax which is designed to go into all nooks and crannies including hair-line cracks in the metal work
  • Cavity wax should be applied via small insertion holes using a special lance extension wand into doors, sills, insides of the body frame rails, rear wheel arch and all other internal surfaces. Do this be inserting the wand all the way through the holes and spraying as you pull and twirl wand out again. This process will ensure good coverage. 
  • Underbody rust proofing - apply DINITROL 4941. It gives an even, thin coverage then dries to a tough, thick, rubbery under-seal to protect against gravel, salt and harsh weather conditions
  • Apply to the wheel arches and get inside to spray into the lip of the arch
  • Replace the rubber plugs into their holes 
  • Test to make sure none of your cars drain holes have become blocked with underbody wax

The rust proofing process using Dinitrol products has been said by many DIY enthusiasts to be a lot less messy than the application of Waxoyl.

After your Mazda MX5 rust proofing we recommend that it should be inspected every year there after for signs of corrosion damage. Any small areas where the underbody coating layer has become damaged from stone chips or contact with the road surface should be repaired and rust proofing applied.

Rust appears to be the number one problem with the Mazda MX-5. If you want to preserve yours so it remains in excellent condition then rust proofing is highly recommended. We hope that this article has helped understand the process involved so you can decided whether to purchase a rust proofing kit and do-it-yourself or take it to a treatment centre.