Corrosion on A pillar

[VinylFan]

Hi

I have hopped over from XK8 forum as I have an early XK .

I am looking for a x308 or 350 and have read as much as I can take I . I went to see a 4.2 sport today. Sellers were Jag fans and there were 5 on the drive!
The car drove well and looked had service upto 2012 then a gap until another service. They didn't try to hide anything and told me what they knew of the car and I could speak to the previous owner anytime.

However when we were getting down to the nitty-gritty, I saw paintwork blistering on the top of the A pillar. There was none on the outer side so it was spreading from the windscreen outwards. I pointed this out and said it was my belief, although I was no expert that it it would entail removing the windscreen to repair correctly.

I have seen this many times on cars and it does entail removing the screen.

My question is, is this unusual and I am correct in my thinking?

We didn't leave on the best of terms however it seemed a good car to me, until I saw the bubbling/corrosion. A shame as it presented well

Many thanks for any advice

Kind regards

Pat

[BrianG]

Hi Pat,
You don't say what year the car in question was; it seems the earlier cars did seem to suffer more from paint bubbling due to minor corrosion underneath the paint due to poor preparation. Even later ones can also have this problem to some extent if stone chips etc are not repaired. I've not heard of 'A 'pillar corrosion being common; usually it's corrosion on corners of doors (as my 2006 model does) plus also a more curious form of paintwork defect called filiform corrosion, which you may have heard of, and which looks a bit like 'feathers' spreading under the paint.

The good news is that with aluminium, unlike steel, the corrosion does not spread significantly into the metal and if treated properly it should not recur. You are correct that the windscreen probably would have to be removed to do a proper job, but if they are reasonable sellers you should be able to negotiate a better price, unless it was already discounted to allow for the defect.

[J44EAG]

Corrosion on the ali X350 is probably no worse than any other ali car. Fortunately, perforation of the sheet metal is infrequent and cosmetic unsightliness in the form of spoilt paint and a powdery white oxidization deposit is no huge issue. Provided perforation has not occurred, quality remedial re-finishing is a reliable proposition.

Corrosion emanating from under trim pieces really does require trim or other part removal. There is no point in just refinishing exposed areas if it is obvious that further corrosion will be lurking behind fixed trim. In the case of the windscreen, then removal to effect a decent repair, will almost certainly be needed. So it is a "bite the bullet" issue where an A-pillar and a screen are concerned.

If I were to carry out such a repair, I would be employing the services of a vehicle glass business to remove the screen. When I recently had a new screen fitted, the guys were only here for twenty minutes. One screen out and the other fitted. This included removal of the rear view mirror and fitting it to the new screen with a special glue. It may not appear so, but that mirror is a heavy old lump and needs a serious industrial adhesive to ensure it stays fixed to the new screen.

With the screen out of the car and set safely aside for post corrosion re-installation, corrosion repairs to the A-pillar may be commenced. This involves removal of corrosion using flower paper or similar abrasive rubbing paper. Carbon based Wet and Dry papers must not be used to remove corrosion or to flat down damaged paint edges. Similarly, the use of steel tools such as screw drivers, chisels etc should be avoided. Again carbon withing W&D papers of tool steel will micro trace carbon into the ali sheet metal. That is guaranteed to set corrosion off again but in rampant style! Use flower paper only to remove corrosion and flat paint edges. Cleaned up bare metal should be treated with an alodine solution before being primer painted with alodine based two pack primer such as Upoxy which is available direct from the company site. Colour coat and clear gloss coats may then be applied over the top of the primer after wet flatting with P800 production paper. Again, flower paper is to be preferred even though bare metal will have been covered by a few micros of two pack primer.

The screen is again best re-installed by professionals as a hot wire is inserted within sealing compounds to cure the adhesive. Screen work is best done by experienced experts and really does fall outside the scope of even the best DIY guys and their perhaps somewhat basic tool stock. I`d budget at least £500 for the screen and paint repairs. You might need to throw more cash into the pot if the screen were to break when removed or re-fitted....it has been known and all screen fitters will tell you that if an old screen breaks during removal or re-installation, replacement costs will be your responsibility.

Hope that helps.

Mike

[VinylFan]

Hi
Many thanks for your comprehensive replies. You have clarified all the thought's that were going through my mind.

The car is a 2003 4.2 sport with just over 100k on the clock. The marks on the A pillar are spidery and so far under the surface, but just about to break through. They eminate from under the windscreen seal outwards. It's not that noticeable at first because of where it is, however once noticed, like most items related to rust /corrosion, it's not nice.

It does tend to look like veins speading. As to negotiating any further, when I pointed it out to the seller, he and his son were far from impressed, in fact the son walked off with a gesture of the hand and never spoke again. 5 minutes later I was off the property!

Ever since then I was second guessing myself and I have found the more I think about it ,the more I convince myself I was wrong. However you have put my mind at ease.
All I need to do now is find another V8 and they are a little thin on the ground where I am.

Many thanks for both your replies

Kind regards

Pat

[poprivet]

I can't help thinking that if someone is selling one of their five cars it would be the worst one?

[J44EAG]

What Pat has clearly identified is known as Filiform corrosion. When working in the aircraft repair business, I could see examples of it every day on light aircraft air frames. This link will tell you more about this particular form of corrosion.https://www.google.com/url?sa=t&rct=j&q ... 9sqOzyBzC1

Mike K

[VinylFan]

I can't help thinking that if someone is selling one of their five cars it would be the worst one?

Hi
Strangely enough , it wasn't. There were 2 which needed a little TLC but the other 3 were in good condition, another one of which will be coming up for sale soon. This one was in overall good condition, apart from the corrosion, which they didn't want to know about .
I didn't want a car that I need to start spending on straight away. Plus they were not willing to haggle.

Kind regards

Pat

[VinylFan]

What Pat has clearly identified is known as Filiform corrosion. When working in the aircraft repair business, I could see examples of it every day on light aircraft air frames. This link will tell you more about this particular form of corrosion.https://www.google.com/url?sa=t&rct=j&q ... 9sqOzyBzC1

Mike K

Hi Mike

This was parked under a tree , not a huge one, and there were bushes and more trees tobthe left . It was a nice place and they were Jaguar fans. However , that is most likely where it came from. I believe it hadn't had that much use recently as the brake discs had a thin coating of rust on them and it was noticeable they came off when I reversed the car.

Many thanks for the link and everyone's assistance

Pat

[J44EAG]

Filiform corrosion is typical with alloyed metals. Boxite, copper and zinc can be found in the various mixes of aluminum. Dependent on the alloy brew from which a sheet of metal is produced, its resistance or not to corrosive occurrences is highly variable. High zinc alloys are particularly poor at resisting corrosion. It is not unknown that a 7000 Series ali can and does corrode from the inside to the outside. See any condemned Piper Cherokee or Warrior wing joiner to view the explosive pressurisation effect of internal galvanic action. This is known as inter-granular corrosion. In addition, contaminates not thoroughly removed from the surface of the metal before paint finishing, can set off corrosion between the metal and paint interface. This is known as Filiform. I studied these phenomena when undertaking a three year fast course to gain an Aircraft Licensed Maintenance Engineers certification. Rectification of such ills forms a major part of any aero engineers working week.....if it can rot and revert to its natural former constituent material composition, then I guarantee it will. It all makes work for the working man to do! Fortunately, I`m not doing this type of work anymore!!

Mike