E46 Rear Wheel Arch Rust Repair and Respray [DIY]

Unfortunately, rust is a common affliction of the E46, particularly the rear wheel arches. Road grime gets thrown from the tyres up into the arch and, over time, wears away at the paint until the inevitable rust sets in. The rust on my Sapphire Black saloon was getting so bad I decided action needed to be taken to restore some of the pride back into my pride and joy. Here's how I got on...


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Assessing the Extent of the Rust

Concluding my recent trio of cosmetic improvements, this post focuses on the repair of my oh-so-rusty rear driver's wheel arch.

Having warmed up by refurbishing the wing mirror cap and the roof ditch finisher, I was feeling confident in doing a fairly good job of the wheel arch (for a novice). Unlike the previous two jobs, this would involve some fairly scary preparation methods to achieve a decent result.

Let's take a look at what I was working with.






As you can see, tin worm had well and truly set up base camp.

The first job was to mask off the panels I didn't want to damage, namely the side skirt and rear bumper. In a perfect world, I'd have removed both of these parts, but I was limited for time and space.

Rather scarily, this was the first time I'd used the tools I was about to unleash on my pride and joy's paintwork. Nevertheless, to quote Del Boy "he who dares, wins".

Removing the Surface Rust

To tackle the worst of the rust I started off using a very abrasive flap sanding disc (no wheels or tyres were harmed in the making of this post).




I then moved onto a smaller sanding disc to get to the hard to reach areas and to bring the bodywork back to a smoother finish. You'll notice I slid a metal plate into the bumper to body side gap to avoid sanding the bumper.


Scary bit done, you can see the various stages of sanding below. You might think that the 'final' condition isn't great either, however, there was still a lot of work left to do at this point.

Rust Removal Treatment

Once the surface rust had been removed, I wanted to do everything I could to stop the rust from returning. After scanning a few forums and sites on which rust treatments were recommended, Jenolite rust remover came up top. Hey, if it's good enough for the British MOD it's good enough for my 330d!

I bought a 500ml bottle not knowing how much I'd need, but really you'd get away with the 150ml if you're just treating rear quarter panel rust. It's quite thin stuff, so a little goes a long way.

You can grab a 150ml bottle on Amazon here*.

How to Use Jenolite Rust Remover

Quoting Jenolite's website, the process was as follows:

1. Apply Jenolite Rust Remover directly to the rust.
2. Wait 15 minutes, then apply a second application and immediately wipe dry with a clean cloth.
3. The surface will be ready to prime in 30 minutes. Job done!

Applying Car Body Filler

Having hopefully sorted the rust out, the next task was to apply some body filler to smooth out the body work and return it back to it's former glory - handily I already had some U-POL Easy 1 in the garage.

You can pick up U-POL Easy 1 here* and the U-POL BPO hardener here*.

All I've got to say is, Ed China makes applying filler look a lot easier than it actually is. Applying a little at a time I filled all the necessary areas.

Sanding Process

Once the filler had fully hardened it was time to do some more sanding, this time by hand using wet and dry. It looks a mess in the photos but I was actually pretty happy with the finish.

Preparing the Surface for Paint

Prior to painting I used some panel wipe to clean off any contaminants on the surface, any dust, dirt, grease on the surface could affect how the paint adheres.

I got a 1 litre bottle from APL chemicals, the stuff works great, I've used it on loads of jobs now, not just before painting. APL have an Amazon store so you can grab a bottle here*.


I also masked off the area I was going to paint and the surrounding parts, don't skimp out on this part of the prep work, paint gets everywhere. My plan was to 'blow in' the edge of the wheel arch and match the paint to the body side. In hindsight, I should have resprayed up to the feature line in the body side and all the way back to the rear lamps. I'll explain why later.

Paint Process

I followed the same three coat process I used on the wing mirror cap, dusting on the first coats of each paint (primer, colour and lacquer) then applying heavier coats. Again, I used Halfords rattle can paints, professionals and enthusiasts will shudder when they read that but this fix was done on a budget with the tools available.








Despite not painting up to the mask line the step in the paint at the mask line was quite big, clearly noticeable, something I hadn't expected.

I always knew I'd need to blend the edge in but didn't realise quite how much blending would be required. Carefully, using some 1200 grit wet & dry, I sanded the edge until it was in-perceivable.

Final Polish and the Results

Finally, using my DAS 6 PRO, I polished the paint back to a gloss, also correcting as much of the orange peel effect as possible.

Fortunately, (or unfortunately) it was bright sunshine on the day I did the polishing. Even after I'd finished you could see the 'tide' mark where the two paints blended together, the Halfords paint not entirely matching the original. It's for this reason, if I were to attempt the job again I'd have sprayed all the way up to the feature line to mask the paint blend edge.


Having said that, it was only visible at that angle in direct sunlight, any other light or angle and you couldn't see it, so I was pretty darn chuffed. Was it body shop quality? No, definitely not. Was it good enough for a job that cost under £20 on a car worth only £2k, absolutely yes.



Let me know in the comments below what you think. Have you had a go at rust repair on your E46?

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