(First posted on MLR forum in July 2015)
These Evo’s are getting on a bit nowadays and rust can be a very serious problem for some of them. I’ve been under mine enough to know it’s not perfect but is certainly nowhere near as bad as some out there. So I really wanted to make some efforts to protect the underside etc to help get many more years life added to the 17 it’s survived so far.
It was undersealed when it was imported which must have helped for a while but it tends to dry out, harden and crack over time. This had clearly happened in a few areas on my car so I reapplied underseal and some waxoil in a few areas when I bought the car but that was 3-4 years ago now. I figured it was time to have another look at it all. I got my chisel, wire brushes, grinder and anything useful out to strip any old underseal, paint and rust off ready for application of some Hydrate 80 followed by 2 coats of paint then underseal with waxoil.
The sills seemed as good a place as any to start.
Stripping back to fresh metal…
…and some not so fresh metal
With all loose stuff removed until I reached fresh metal. Next I applied Hydrate80 to kill any remaining surface rust.
Next a couple of layers of paint.
Same treatment on the other side
I left that to dry properly for a couple of days then got the underseal out. This Hammerite Underbody Seal with added Waxoil scored highly in a long term test by one of the classic car mags. It’s sensible money, easily available and can be thinned with white spirit to spray. I opted to brush it on under the sills as it’s not a large area and a couple of coats can get it on nice and thick. Having the white paint underneath made it very easy to ensure good coverage.
It’s not pretty but that’s not the point. It should do a decent job for a few years. All these underseal type products tend to recommend reapplication after 2-3 years so it will certainly want checking about then. This is obviously only the start and I’ve done more, just got to go through the pictures to get rid of all the out of focus/pointing in the wrong direction ones. Doing this job and getting pictures while crawling around under the car is a bit of a bitch! Worth the effort though. 
