Aluminium/Alloy valve cap warning

Daveotto

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If like many during the long months of waiting for my car I agonised over what valve caps to buy and finally bought and then fitted on day one of ownership. However, after 4 months and 4000 miles, found earlier this week with all the wet weather that two of them had welded themselves to the metal valve stem due to corrosion

Short trip to local garage who managed to get them off without having to replace the tyre valve and now consigned to the bin and replaced with standard black plastic ones.


Moral of the story...fit aluminium/alloy valve caps at your own peril!!!!!

Pic of offending part attached
 

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I've had similar problems but not with the genuine Audi items, a small smear of anti seize also helps.
 
You are ok if you squirt them with a bit of WD40 first. I personally hate the black plastic ones so have always swapped them with no problems after a little bit of WD40...
 
Thanks for the warning, I was considering these at one point, won't bother now! It's such a tiny item I'm just not that bothered about them being plastic!
 
You are ok if you squirt them with a bit of WD40 first. I personally hate the black plastic ones so have always swapped them with no problems after a little bit of WD40...

Might have been the particular valve caps I had, hence posting the pic. but I tried WD40 but to no avail, all I manged to do when i put pliers to them after soaking them in WD40 and leaving for a good few mins was to turn the whole valve, hence trip to the garage. If was only one would have done it myself but with only one spare......
 
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Might have been the particular valve caps I had, hence posting the pic. but I tried WD40 but to no avail, all I manged to do when i put pliers to them after soaking them in WD40 and leaving for a good few mins was to turn the whole valve, hence trip to the garage. If was only one would have done it myself but with only one spare......

Sorry mate I meant before you put on to prevent the corrosion occurring.
 
Sorry mate I meant before you put on to prevent the corrosion occurring.

I did when first fitted but not since...thats probably the mistake, quick squirt of the stuff every time you check the tyres...lesson learnt
 
Hi, is this not a problem with the type of metal used on the valve itself and the reaction to aluminium screw cap? I think I have read about this before...
 
Hi, is this not a problem with the type of metal used on the valve itself and the reaction to aluminium screw cap? I think I have read about this before...

Think that was part of the problem, reckon they were mainly if not all aluminium, so was a horrendous amount of white oxide on the valve stems when the caps were removed.
 
There are chrome plated steel ones and aluminium ones out there, stay clear, they both oxidise. The nasty things about the plain plastic one though is that they don't generally have any seals inside. Even the OEM metal ones have a seal. Just another thing to help should there be any seepage from the valve itself, which is not common these days.
 
That's incredibly unlucky... I've had cheapish ones off ebay on mine for ages now and they're as sweet as a nut to remove.
 
Has some on my last A1 which were knicked, I found out later that they can have problems sticking to the valve, so it was a blessing in disguise.

Dont think I would bother in the future, although the plastic ones are a bit naff, they dont have the chance of being knicked or sticking to the valves.

Thanks for the warning Dave, just reinforces why I shouldn't buy them
 
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