Not every job in the workshop is a classic restoration or performance project. A lot of what keeps us busy is straightforward, necessary repair work that keeps everyday cars safely on the road. This Ford Fiesta came in for exactly that — MOT welding to the offside sill and the offside rear inner wheel arch.
Modern cars are far better protected against corrosion than they used to be, but once rust takes hold in structural areas, it moves quickly. Sills and inner arches are common weak points, particularly on cars that have seen several winters. Road salt, trapped moisture and debris build up behind plastic liners and under trims. From the outside, it can look minor. Underneath, it often isn’t.
In practice, we see plenty of cars fail their MOT due to corrosion within the prescribed areas close to suspension mounting points or seatbelt anchors. That’s when welding becomes essential, not cosmetic. The structure needs to be sound. There’s no point patching over rust just to scrape through a test.
During this Fiesta, the offside sill had deteriorated enough to require a full section repair rather than a small patch. The inner rear wheel arch had also weakened, as is common. Once rust starts inside an arch lip, it tends to creep inward where it’s less visible.
At White’s Bodyworks, MOT welding is approached the same way whether it’s on a supermini or a classic. The affected areas are cut back to solid metal. That’s the key point. Welding to thin or contaminated steel just creates problems later. New steel sections are fabricated to suit, properly shaped and securely welded.
Most people don’t realise how important it is to properly prepare and seal after welding. Bare repairs without proper protection will simply rust again. Once structural work is complete, we treat and seal the area to give it the best chance of long-term durability.
This wasn’t a glamorous job, but it was important. The Fiesta didn’t need restoring or upgrading. It needed safe, solid repairs so it could pass its MOT properly and continue in daily use. Cars like this often have years of life left in them, provided corrosion is dealt with properly rather than ignored.
MOT welding is about keeping vehicles structurally safe. Done correctly, it restores integrity to areas that matter most. It’s the sort of work that doesn’t draw attention, but without it, plenty of perfectly usable cars would end up off the road unnecessarily.
