Mud Behind Wheel Wells: 2 Shovels Needed!

Hello everyone!

I had an idea the day before yesterday. Since it's known that it's winter, and I want to protect my galvanized Golf 4 from stone chips and salt water on the entire underbody, I thought I would order a pair of original mud flaps.
Okay, so I removed the three Torx screws and looked under the wheel arch liner, near the rocker panel, and OH MY GOD! There was wet mud accumulated in some crevices. I can only say that, according to the previous owner, the car has 113,000 km and was frequently driven on the highway.
Despite that, a whole shovel full!! And on every page, mind you.
Well, I don't know, but I removed it, hoping that installing splash guards will contain it.
Okay, also noch etwas zu ULF!
I don't know the specifics of the construction of the Polo 9N, but it might be worth reducing its overall weight by approximately [amount], and that's not an exaggeration.
2 kg. And now Volkswagen is considering whether to install a real spare tire or a puncture repair kit.

Best regards, Frank.

Hi!
Okay, I can only confirm that! When I installed my new parts this year and freed up the wheel arches, a bucket of mud and dirt also came out. I had to really use my screwdrivers to "plow" and get all that stuff out .
But I believe that it's hard to prevent that. It won't be easy to make the wheel arch waterproof...

Sure, here is the translation of the text from German to English:

"MFG" is an abbreviation for "Mit freundlichen Grüßen," which means "Sincerely" or "Best regards" in English.

Hello,

"It was the same with my Golf 3. When I recently had the sills re-sealed (supposedly for a long time), I also removed the front wheel arches. The result: approximately 1 kg of natural material on each side. Although everything was rust-free underneath the sealant, I also applied a layer of wax there as a precaution. Probably the cavity will fill up again very quickly anyway."

Best regards,

I completely agree with the recommendation. However, I wouldn't use a screwdriver to remove the dirt. You could damage the paint and possibly the zinc coating, and then rust will appear much faster. Instead, use a piece of wood (like a broken ruler) for the bigger pieces. From now on, I'll clean everything with warm water, dish soap, and a brush at least once a year during tire changes, and that should be enough. Removing the wheel arches with a cordless screwdriver takes less than 5 minutes.

Regards,
DirkP

...it's better not to scratch at it, but simply rinse it off with a garden hose. This prevents damage!

Sure.

Lots of water, and possibly some pressure.
Using a high-pressure washer will only spread the grime around.

In my G2 sample, the material even had annual "rings," which are layers of sediment with different colors.

m;

"On my Golf 3, I cut a hole in the lower part of the wheel arch so that dirt can be washed out. Before doing that, I cleaned everything thoroughly and applied a thick layer of hot wax."

Quote:

Removing the wheel arches takes less than 5 minutes with a cordless screwdriver.

"Don't you think the threads might wear out eventually? They're rarely designed for constant, repeated use."

Quote:

It won't be easy to get the wheel arch sealed.

Perhaps you could seal the edges with acrylic or silicone?

It looked the same for me. The debris and larger pieces probably came from the top, through the water reservoir.
@Peugeot 308 drivers
Most of the screws are housed in plastic sleeves, which are inexpensive and can be easily replaced if needed. Therefore, an annual cleaning should not be a problem.

"To HDI sealant users: Acrylic is hygroscopic, meaning it attracts water. Silicone typically uses acetic acid as a solvent, which also creates the characteristic odor during application. This acetic acid is not a problem for materials that are acid-resistant, such as your bathtub, sink, or bathroom tiles. Additionally, silicone remains flexible for a long time, but it also develops a surface that attracts dirt. This means that all sorts of grime, dust, or similar substances will stick to it."

In the case of the wheel arch shown, it would be necessary to investigate the source of the decaying material that accumulates there. If it originates "from above," from the water tank, which also typically serves as the intake point for cabin air, then it might be possible to prevent the ingress of this material by installing a fine-mesh grid. This would somewhat reduce the amount of work involved in clearing out the wheel arches behind the wheel arch liners. However, after a certain period, I would check the effectiveness of the additional grid and still occasionally remove the liners. If little or nothing accumulates afterward, then rinsing with water from the water tank during car washes might be sufficient to flush out small particles such as birch pollen, sand, or dust.

The dirt on the photo of the Golf is 95% coming from the top of the water tank drain. This is also perfectly normal.
You can tell if it's full when the draining water starts coming out of cracks and holes in the inner fender liner at a higher point, rather than just from the bottom. At the latest, when the soil reaches the end of the drain, the water will back up in the reservoir and overflow through the ventilation on the passenger side, entering the interior of the car (Lupo, Polo 6N2).
After 6 years, I had approximately half a 10 kg bucket of material on the right side, and about half of that amount on the other side, where the fender had been removed 3 years ago.

Regards,

Olaf.

Hi.

The leaves will likely end up behind the wheel arch liner, over the water tank.
I'm not sure about the sand layers, though. In my opinion, they come from the gaps that are always present between the shell and the metal, and originate from dirt and debris kicked up by the tires.

That much sand simply can't get over a "normally driven" car without the paint being sanded down.

m;

I can only speak from experience with the Lupo (but the construction is very similar to the Golf IV)... and I can't rule out that some of the dirt actually gets in through the wheel arch. However, this stuff definitely gets baked in by the constant water from above. You often see the characteristic "growth rings" that form, which unfortunately aren't visible in the photo.

However, it's important to remember that everything that lands on the windshield and part of the roof eventually ends up in the windshield washer reservoir. This can be a significant amount of dirt, especially if you regularly park under trees.

Well, it probably won't be possible to figure it out completely without "experiments."

Regards,

Olaf.

Sure.

The water hardens the material.

But the tires churn up significantly more dirt than the roof (usually .

Rinsing thoroughly is definitely a good idea.


m;

I also think it's road grime that's splashing onto the inner wheel arch and then running down, or perhaps getting behind the plastic cover.

"Back then, I tried rinsing it out. I removed the side markers and used a garden hose, and at first, a bunch of dirt came out, followed by clear water. I thought that would solve the problem... But rinsing doesn't really do anything. It might flush out the loose dirt, but the "mineral deposits" are still there. The best thing to do is to remove the trays once a year and clean them. Or, you can treat everything with wax to prevent the dirt from causing corrosion."

Hello,
I checked today and was surprised to see a pristine gap between the wheel arch and the body on the driver's side. After almost 5 years, there was virtually no dust in there.
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Auf der Beifahrerseite habe ich zwar die Torx-Schraube nicht gelöst, aber man kann beim 3BG auch so sehen, dass der Dreck nach unten anscheinend gut ablaufen kann?! Hm...
haithamina