Whilst checking my 1995 X300 over recently, I spied a small bit of surface rust just below the rear lights. (My car is virtually rust-free and solid underneath in original condition, with 122k miles, driven all year and lives outside all year far North Scotland.) I removed the rear lights and tackled the rust with a 60 grit flap-wheel on my drill. Oh-Dear-Me.........The area was considerably worse than I expected, mainly because the rust was well established on the inside of the panel. This is because of an underside open area, that allows all manner of road-mess to enter the area without ever being properly cleaned, and with no protection afforded to the inside of the panel except a thin undercoat.
I had previously a few years ago found the start of what could have potentially been serious rust behind the chrome boot escutcheon, well this is very much the same sort of thing. Hidden, unless checked before it's too late, and not easy to get at the inside to prevent further problems. You can see the open area in the second picture looking down through the large round hole where the light covers the base.
Once I'd opened this can of 'rust-worms' I decided to get the grinder, and grind both sides, and had to drill-out the drivers side. You can see from the pictures, the first one of the rear of the car taken in February this year, the car looking not bad with no real signs of rust. Then the pictures with the lights removed, and the rust removed from the outside surface, and drilled-out on the off-side. I held a small piece of mild-steel up to the inside, and a couple of blobs of weld. Then grind flat. I scrubbed the hidden area on the inside with a small wire brush attached to a flexi-drive off the drill, then treated all areas with Hydrate 80. Melted a bit of brazing-rod into the inperfections after grinding and smoothed it off with 600 paper. Painted. Job finished today putting the lights back in place.
Not an easy job, but well worth checking behind that bit of panel by sticking your fingers through the big hole. Mines an early X300 and didn't have any protection, perhaps the later ones are different. Best to find these problems before they're causing bigger problems. I hope someone benefits from knowing this.
Peter
