It is that most wonderful time of the year – where I know the red 330d should be prepared for its January MOT. The government’s MOT history site is very useful in this regard because it means I can easily be reminded of any MOT advisories from last year without having to dig around for paperwork. As an aside, it also lets anyone view the MOT history of any car, which is useful in a variety of circumstances. Check it out!

https://www.check-mot.service.gov.uk/

It turns out that last year’s test was relatively straight forward and only noted some corrosion on the rear suspension springs.

As luck would have it, I had two pairs of new replacement springs in stock(!), so I got the 330d into the garage and prepared for what I expected to be a quick job.

Removing rear springs on an e46 is simple: car up, wheel off, disconnect the shock absorber from the hub, and use a long bar to lever the spring out. Just as I was getting into that though, I then spotted some rust, and that’s just not something I’m willing to entertain. So the job rapidly transformed into a comprehensive rust search and destroy mission around the rear of the vehicle.

Here’s the issue. This shows the corrosion on the spring, corrosion on the car body, and I’ve also highlighted the battery tray where I had already brushed away rust flakes before thinking to grab my phone to document matters.

Fortunately, neither the battery tray nor the car body was badly corroded. It was just surface rust that brushed off easily and the underlying metal wasn’t weakened. Armed with a manual wire brush and a bunch of wire brush drill attachments, I blasted everything clean, used white spirit to degrease, applied Kurust to further treat the surface, degreased again, them applied two coats of Hammerite direct-to-rust black paint. If you’ve not used that before, it’s a thick treacle-like coating which feels half-way between ordinary paint and traditional underseal.

I then got a bit carried away, and cleaned down and coated the whole battery tray. It shall not rust on my watch!

I had to drop down the fuel filler pipe, the exhaust and remove various plastic panels to get good access to the underbody. I made a point of cleaning up everything as I went along. Fortunately the left side of the vehicle was in much better condition, but in any case I’ve firmly guarded against corrosion under there.

Eventually then, having sorted all that out, I returned to the matter in hand: replacing those springs. Here’s a new spring (left) with an old spring (right).

Getting the new springs in was something of a chore. My spring clamps are too long – they’ll clamp up the spring alright, but the length of the tool itself is longer than the springs, so having clamped them up I still couldn’t get them in place.

In the end I managed to lever them back in with a long bar and sheer determination. There’s no discernible difference in the way the car drives, but there’s significant peace of mind in knowing that all advisories from the previous MOT have been addressed, and that tin-worm has been detected and firmly addressed.