Rust...

Hejira

New Member
Hello all,

I’ve been steadily compiling a list of things that need to be replaced/repaired on Brienne and have been wondering about rust on exposed components. Obviously it’s much less of a problem for A2s, given the aluminium frame, but there are still many of her steel parts looking worse for wear.

E.g.

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I didn’t worry too much about corrosion on my Micra (as long as it was safe). She was already heavily rusted by the time I got her and restoring those parts weren’t worth the hassle/money. My approach to Brienne is different: she’s much more to me than just her current market value, and I want to keep her running as long as possible.

So, having little experience with this issue or it’s prevention, I’ve got some (probably quite elementary) questions:

- Does surface rust on exposed parts always spell future problems, or is it merely a cosmetic issue for some parts? Obviously severe rust (presumably beginning as surface rust) will always cause problems eventually, but when researching this online some people suggest surface rust is nothing to worry about for some parts (e.g. drive shafts).
- Which parts are particularly susceptible to corrosion and which of these are particularly vital (i.e. structurally, mechanically, or because they will cause wear to other parts)?
- What rust repair techniques do people use?
- When is it necessary/worth repairing surface rust? (I appreciate this might differ depending on the part)
- Are both the block and head of the 1.4 TDI aluminium?
- DIY rust-proofing ideas?
- Any other useful information/resources?


I appreciate these are very general questions, but I’m really after any/all relevant information. Whenever I see rusty exposed components I get concerned, but I’ve come across many mechanics who don’t seem that bothered. I don’t know if that’s my ignorance, or whether they’re viewing the car as ultimately disposable, whereas I see it as a restoration project.

Thanks


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Most of the bits in your photos are consumables. So changing them is the best option. The brake discs and drop links aren't expensive and you can buy coated discs and stainless drop links that should keep corrosion at bay for a couple of years.
The brake splash guards are about 10 quid each from Audi. I've replaced mine twice during my ownership. Replace when you do the discs and paint them with hammerite before you fit them.
The rear axle is prone to surface rust. It's cosmetic and I've never read about one failing. Rub it down. Clean it and coat with rust inhibitor and hammerite or the expensive option is to get it shot blasted and powder coated. I'll do this on mine eventually.
The front wishbones can fail. There is a current thread on here about it. Worth replacing these with cast or forged replacements. Mine are rusty on the surface but structurally sound. I've always asked for them to be carefully examined each MOT.
The heat sheild fixings can rust and become loose and rattly as a result. This is due to reaction between the ferrous metal fixings and the aluminum I believe. Again worth giving these some attention if you intend keeping the car long term. There is threads on here detailing replacement if you Google A2oc heatshield.

Once you clean /treat /replace you can waxoyl the underbody for protection.
 
The 1.4 TDI is all iron (the 1.2's which were all LHD were aluminium though).

In terms of component surface rust, my take is that brake discs and ARB droplinks you'll go through anyway, backing plates are only there to keep the worst of the water off the discs and are not expensive in the grand scheme of things. The important bits of the calipers are on the inside and are best kept rust-free by changing the brake fluid every few years. Driveshafts I don't know about, but where you really need to keep any eye out is the lower suspension arms. You have the later pressed type, that tends to rust out from the inside. For peace of mind, replace them with the earlier cast type. Plenty of threads to search for on here about those.
 
Does surface rust on exposed parts always spell future problems, or is it merely a cosmetic issue for some parts?
Things like the anti-roll bar will develop surface rust, but it's just a cosmetic issue. The drop links will chew their ball joints well before the rust becomes an issue, etc, etc. I'm just repeating what's been said above, really. There isn't a lot to worry about.
The front wishbones can fail. There is a current thread on here about it. Worth replacing these with cast or forged replacements.
You have the later pressed type, that tends to rust out from the inside. For peace of mind, replace them with the earlier cast type.
This is the biggie. Later A2s were fitted with cheap, pressed steel wishbones. When these rust too much, it becomes a major safety issue. They'll need to be replaced with the earlier cast type. This job needs doing on Anna's A2 at the next service as the ones on her Colour Storm are getting a bit too far gone for my liking. If one breaks through whilst driving on the motorway, it could be catastrophic.

Cheers,

Tom
 
Hello,

To protect the wishbones spray WD40 inside the holes. Removed any flaky exterior rust and smother in grease.
The rest of the rusty bits can be covered in, yes you guessed correctly, lots and lots of grease.

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On the 1.4 tdi engines the block is cast iron but the cyl head is aluminium

As others have indicated, most of the rust on A2s is cosmetic but if you like the idea of tidying up any of the smaller components, Phil Ward posted lots of info on de-rusting and zinc plating parts

Cheers Spike
 
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